Yuki and Zero met at ages 12 and 13 respectively, when Zero was taken in by Kaien Cross into his home. Yuki immediately took to the young boy and looked after him the night they met, cleaning the emotionally fragile Zero's wounds. She promised to be with him always after she discovered him distraught one night, tearing at his neck. Yuki would often stay up at night with Zero, patting his head when he had nightmares to help him to fall back asleep. Yuki's nature overcame his distance and her presence helped his nightmares to cease. However, Zero began to act aggressively towards Yuki after learning of her love for the Pureblood vampire, Kaname Kuran, not wanting her to touch him with the hands she touched Kaname with. He seems incredulous at Kaien and Yuki's stance on the vampire race. When Zero began to panic, fearing his transformation into a vampire, he accidentally lashed out and hurt Yuki. When he found himself attracted to the smell of her blood to his shock, he swore to the Chairman that he needed to become stronger. Yuki accidentally admitted she was scared of Zero. When Zero tried to tell her his secret, she revealed her fear about being attacked by the vampire in order to empathise with Zero. Instead, Zero became angry at himself, so he tried to push her away, deciding against telling her his secret. This was the beginning of Zero deliberately trying to put distance between Yuki and himself, to the point where he refused to be adopted by Kaien because he did not wish to become a part of Yuki's family. Yet Zero still grew attached to Yuki and his affection for her grew throughout their adolescence, even sitting outside her room for the night when she became sick. When Yuki went to see Kaname at the school and was disturbed by the encounter, Zero observantly told her if she was not scared, she would not tremble. He is very protective of her, which Kaien used to get Zero to attend school, after Zero stayed back a year of high school and continued to refuse to enter because he despised the idea of vampires and humans going to school together. Zero agreed to attend school when Kaien told him that Yuki would have to be the school guardian of Cross Academy all by herself if Zero did not go to school.
In the Manga
After his vampire instincts fully awaken, Zero becomes increasingly distant towards Yuki. Frustrated at being pushed away, Yuki pursues Zero and he loses control, biting her and drinking her blood ravenously. Yuki discovers that Zero was bitten by a Pureblood vampire, turning him into a vampire too. Finally beginning to understand Zero's anguish, Yuki arrives just in time to stop Zero from committing suicide. She then stops him from leaving the Academy, promising to stop him herself if he loses control.
Following the incident, Kaien gives Yuki a hunter bracelet that will tame Zero using a blood spell. It is also revealed that the tattoo he had gotten in his adolescent years, with a symbol that matches the one on the bracelet, was supposed to stop his transformation into a vampire. After visiting Kaname in the hopes he'll keep Zero's secret, she meets Zero outside. She learns that Zero isn't affected by sunlight the way most vampires are, due to not being born as one. She also blurts out that vampires and humans aren't suited for each other, something she immediately regrets saying in fear of offending Zero. However, in response Zero gives Yuki a gun used to kill vampires, telling her to kill him when the day comes and he loses control.
On a trip to town to run errands, Yuki finds a shirt for Zero. She remarks that Zero needs someone to take care of him, and likens him to a younger brother. Zero quickly shrugs off her remark, reminding her that he's a year older than she is. The two exchange banter and Yuki feels like they are back to the 'old days', despite knowing now that he is a vampire. Zero later protects Yuki from a rogue vampire.  At Takuma Ichijo's party, Zero once again begins to thirst uncontrollably and leaves abruptly, with Yuki quickly in pursuit. She finds a packet of blood tablets, but Zero reveals they have only made him sick since he bit Yuki and he can no longer tolerate them the way he once did. He then tries to attack Yuki again and she pulls him into the pool, stopping him.
Yuki protects Zero from Toga Yagari when he injures him during the pool scene, and it's revealed that Zero was a former student of his. Though she's kept out of their later discussion in private, it's clear that Yuki is deeply concerned for Zero's welfare after learning about his tablet tolerance, realising that he really could eventually become a Level E. After that, she makes the decision to save Zero in the best way she can. Yuki takes Zero into the bathroom and, despite his protests, coaxes him into drinking her blood. She reiterates to Zero afterwards that she'll be the one to stop him and she'll 'tame the beast' even if he hates her for it, because she won't let him die. Zero asks her how he could hate her, but quickly changes subject. Though she asks Zero to promise her he'll come to school, he doesn't turn up. Realising there's trouble, Yuki intervenes before Toga can pull the trigger and kill Zero in his quarters. Zero redirects the gun and Toga reveals that the two had made a promise for Zero to die at Toga's hands if he should become a vampire. After Toga leaves, Zero comforts Yuki with a pat on the head, telling her not to cry as he won't 'run away' anymore.
It's revealed that, despite taking Yuki's blood, Zero still thirsts and barely keeps control when watching over a sleeping Yuki. She later finds him in the bathroom and jokes about giving her blood 'willy-nilly' when she has the responsibility of providing Zero with blood 'forever'. This is following a conversation regarding her feelings for Kaname earlier. Zero pins her to the wall, giving her the impression he's going to drink from her, but pulls away shortly after and tells her to get out. Yuki responds with annoyance, throwing a towel with her bra inside at him while calling him a jerk. She snatches the bra back and warns him she'll be angry if he tests her again. The next day Yuki follows Zero during a hunt and is attacked by a Level E vampire. Zero rescues Yuki and executes the vampire in front of her.
While on patrol after the arrival of Maria Kurenai, Yuki finds Zero stood beneath a tree. She initially jokes about Zero loafing off on his job. They then proceed to have a conversation about the hunting incident and Yuki reveals she was worried Zero had run away and would go off one day in search of vengeance without telling her. Though Zero tries to shrug her off, Yuki reminds him that it's her who will kill him and so she should know these things. When Maria approaches, Zero suddenly becomes aggressive, forcing Yuki to protect Maria from him. After this event, he tells Yuki while helping her with work that the bite given to him by the vampire who turned him was throbbing. Yuki puts her hand over his and tells him she's worried. Thinking he may be sleepy, she goes to make him coffee. However, Zero stops her, taking her hand in his. He reveals to Yuki, who asks if he wants blood, that she was the reason he was able to carry on living.  Still worried after he leaves, Yuki follows him and finds out that inside Maria is Shizuka Hio, the woman who turned Zero. Before she can intervene, Kaname puts her to sleep and takes her memories of the event away.
Despite Kaname's efforts, Yuki regains her memories and confronts Maria. She, or rather Shizuka, reveals that she can save Zero from becoming a Level E. In exchange for her aid, she has to either be give herself to Shizuka or kill Kaname. Zero turns up bloodied while the ballroom is being prepped for the ball, apparently searching for Maria/Shizuka. Yuki takes him into another room and he warns her to stay away from Maria/Shizuka before drinking her blood. She notices that he isn't hesitant when he drinks from her and reflects on that bargain offered by Maria/Shizuka. Zero also reflects on how Yuki's blood calmed him, feeling disgust at himself. Yuki arrives at the ball and adjusts Zero's clothing, putting a rose in his pocket to finish the look. Zero asks how she can smile and Yuki tells him it's because she wants him to smile too. After dancing with Kaname, Yuki leaves to seal the deal for Zero's life, offering herself as a sacrifice. Before she can bite Yuki, though, Zero arrives and stops them.
Yuki protects Shizuka from Zero, revealing to him that she can save him from descending to madness. Despite this, Zero still tries to attack Shizuka, forcing Yuki to try to tame him with her bracelet. Shizuka's voice puts Zero under her control and she has him hold onto Yuki tightly as she takes his blood as punishment for being tamed by Yuki. Shizuka then tells a protesting Yuki that she's cruel for making Zero suffer with the choices she made, and Yuki wonders aloud if he'd forgive her for it. Zero breaks free of the control before Yuki can be bitten and protects her from Shizuka, though he's still weakened by her influence. She mocks him, prompting him to break free completely by shooting himself with his own gun in the leg. He then fires at Shizuka, with Yuki once again trying to intervene. Zero reveals that he was living for the day he could end Shizuka's life, and Yuki voices a deep fear about Zero's future once his revenge had been completed, asking what he planned to do afterwards. Shizuka answers her question - Zero wanted to die with her once he'd killed her.
While Shizuka is with Kaname, the reunited twins Ichiru Kiryu and Zero have a tense confrontation. Yuki tries to stop them from fighting and is protected from Ichiru by Zero. When Kaname rips out Shizuka's heart, the scent of blood alerts Zero and Ichiru runs to find her. Yuki stops Zero before he can follow, reminding him of his lack of answer before and asking him of his intentions following Shizuka's death. Zero confirms that he does want to die with Shizuka, and he doesn't want Yuki to become a vampire - especially not for his sake. He embraces her and tells her she doesn't need to care for him so much. He then leaves, telling her to stay and assuring her he'll return. After the events of that night, Zero is incapacitated with his injuries and cannot attend class. Therefore, Yuki takes notes for him. She later brings him the notes and offers him blood, knowing it'd heal his wounds, but he refuses. She then tricks him and bites his neck teasingly, insisting that he drink her blood. In response to that, Zero throws her out of his room. She is later caught up with Zero in a confrontation with members of the senate, who accuse him of Shizuka's murder and order his execution.  Kaname intervenes, however, and forces the vampires to retreat.
Yuki speaks about this with Kaien the next day and catches up with Zero afterwards, reporting back on her conversation. Zero tells Yuki that if his gun did indeed kill Shizuka, he wouldn't regret it. Yuki replies that she's glad he didn't give up his life and reminds him again that she's on his side. She then becomes upset that she couldn't be more help to him, and that he didn't get to take Shizuka's blood and be saved. Zero asks her what he is to her, but changes the topic somewhat before she can give him an answer - telling her not to be rash anymore in what she does for him. He leaves, but the question posed to her is still clearly on her mind. Yuki turns up at the boys dorm just before curfew in the hopes of speaking to Zero, but the two end up having to take Hanabusa Aido to Kaien's private quarters as he has ran away from his dorm. While returning plates and requesting more food for Hanabusa, Yuki is caught staring at Zero. He pins her to the wall, insisting she says what she wants to say. She reveals she's afraid for Zero and the time he has left. Zero calls her silly at this, as it is down to him to decide what to do with his life. He asks that she smiles, even just a bit. After dinner, Yuki drops a dish and injures herself collecting the pieces. She then prompts Zero to lick the blood away and he then drinks from her wrist. She is revealed to feel heartache for Zero, wanting him to smile too and not to disappear. She reflects on his question from earlier again, but still hasn't an answer for him - focusing instead on his vampiric traits.
After a Day Class student is attacked by a vampire, Zero is made a suspect by Kaname. Yuki doesn't take kindly to this and protects Zero's innocence. Zero shrugs her protest off due to her being upset after declaring she wouldn't speak to Kaname until he found Zero innocent, but she feels that Kaname has been meaner to Zero lately - something that Zero also shrugs off as he's always been that way. Nonetheless, Yuki is sure of Zero's innocence and sets out to catch the culprit so Kaname will apologise. During the night, Zero has a nightmare that begins with Shizuka taunting him and ends with a bloodied Yuki collapsing in his arms. He wakes up in the infirmary just as Yuki enters, concerned for his state. Frantic from his nightmare, Zero pulls Yuki onto the bed and embraces her tightly, afraid and relieved he hadn't killed her. Yuki forces herself out of his grip and takes his face into her hands, asking if he's alright. He assures her he is and she smiles at him. In that moment he realises that he wants her gentle hands and her smile and leans in to kiss her. However, he stops last minute and rests his head on her shoulder, dismissing his actions as she blushes.
Following the almost kiss, which Zero claims is due to his half-asleep state, it's clear that the event is still on Yuki's mind. Sayori Wakaba, her best friend, reveals that Yuki has been acting strangely and avoiding Zero since the event. After an incident with a vampire child, Yuki finds herself in an underground mansion during a soirée, having been rescued by Kaname. She spots Zero working and becomes flustered as she remembers the almost-kiss yet again, but insists to herself that he told her he wasn't himself and that's all it was. She reveals that she has always felt Zero was like a sibling for all of those years, a childhood friend and a best friend. When she'd met him, she'd wanted to cherish him. She declares to herself that Zero is indeed precious to her. She picks up on his indifferent nature being so unlike hers after the events in the infirmary and uses that to confirm what had happened was nothing.
During the night that Maria awakens and speaks with Zero, Yuki and Zero finally have a proper conversation again. Yuki wonders if her parents abandoned her, but shrugs the thought away quickly before Zero can respond. Despite this, Zero assures her that there's no need to pretend she doesn't care about her past - even with Kaname's support it's scary to not remember. Yuki then confides in Zero about her encounter and conversation with Kaname during the soirée, asking if her heart would be stronger if she was a vampire. Though she tries to assure Zero that Kaname wasn't serious about turning her, he states clearly that he will not allow her to become a vampire - even if Yuki hates him for it.
When everyone leaves for the holidays, Yuki is left to ponder over her lost memories. She takes a bath and reminisces on the past she did remember, noting that although Kaname helped her bear the terrifying nights of being without memories, it was Zero who made those sort of nights lessen. Because Zero was suffering, it took the focus from her own pain and she became desperate to help him instead. However, Zero kept his vampire nature a secret from Yuki for as long as he could, and he couldn't be saved because of Shizuka's death. To make matters worse, she considered being the thing he hated most and confided in him about it. Rather than protect him, Yuki felt she'd hurt him instead. This drives her to try and remember her past, not wanting to be problematic anymore. Zero comes to check on her and she finds herself in a bathtub of blood, something she finds quickly is an illusion. Zero almost rushes in to her aid, but she reassures him quickly that she's okay. However, before he can leave she grips onto his shirt, requesting him to stay with her for a while. She explains that she tried to remember her past, and in return Zero offers to help her by taking her to look at the society's records.
Yuki, Zero and Kaien go to the Headquarters of the Vampire Hunter Society. Upon arrival one hunter mocks Zero being tamed by Yuki, and Yuki is quick to fire back at him. Before things can escalate, the President arrives and defuses the situation. He asks if Yuki is his girlfriend, which flusters her, and Zero deflects the question by stating their intentions to see the reports from ten years ago. Yuki is hesitant at first when taken to the archives and Zero asks if she wants to stop. Yuki refuses though, admitting that she's nervous, and Zero rubs her cheek comfortingly - making her blush and touch her cheek afterwards. While Yuki is leafing through the archives, Zero is shown suffering with thirst in another room. The President proposes he takes Kaname's blood to delay the fall to madness, something Zero does not want to do. The record Yuki needs sets on fire and she cries out, prompting a struggling Zero to return to her side and protect her.
Zero finds Yuki in the girls dorm at night by herself. She says she wants a quiet place to think and scolds him for coming to the girls dorm, even though it's the holidays. She then offers for him to sit beside her, which he does. The two of them speak about Yuki's past - the records burning up and the hallucinations when she tries to remember. She starts believing that someone has taken her memories, and also starts suspecting that person could be Kaname. Noticing Zero gazing at her, she places her hand on his cheek and runs it up through his hair, asking why he looks worried. Zero asks her in response if she doesn't want him to worry. Yuki smiles at him, moving her hand to his shoulder, and says she doesn't want him to waste his time worrying about her when he should be focused on himself. Zero grabs the wrist of the hand on his shoulder and leans close. This reminds Yuki of the almost-kiss, and she is quick to remind herself it happened because Zero was not himself. Zero leans closer as she thinks about this and bites her neck. She notices he's drinking far more than usual and forces him off her. Zero firmly tells her that she's his victim because the only way he can carry on is by drinking from her. However, in return she can make him suffer or worry or drag him into danger because he will always be sinful, and so he willingly will use his life for Yuki. Yuki grips his shirt and cries over her past while he strokes her hair and comforts her.
After the holidays, Yuki finds her hallucinations are becoming more severe. Zero finds her in a corridor after talking with Kaname, but she reveals she hasn't been able to ask about her past. She notices Zero's eyes are the colour of blood, but he shrugs it off. On Yuki's behalf, Zero confronts Kaname about her lost memories. Kaname attacks Zero and reveals that Zero's feelings are the same as Kaname's. Zero confesses that he only wants Yuki to smile from the bottom of her heart, and he doesn't want her to sacrifice herself for him. For Yuki's sake, therefore, he drinks Kaname's blood. Ichiru joins the Day Class and remarks about Zero caring for Yuki being surprising as his taste in women was once good. Yori uses this to tease Yuki about Zero cherishing her. Ichiru also comments about Yuki's recklessness making Zero worried just as Zero turns up. Zero shields Yuki from his twin and after the confrontation she yanks Zero's hair out. She realises that something has changed in Zero and grasps his forehead to check for a cold, making Zero remark that she's particularly grabby. Before Zero can leave she asks him to accompany her to the Moon Dorm to speak with Kaname. Zero pokes her head and tells her he'll do it and that she has to stop frowning.
Shortly after becoming Kaname's lover, Yuki is reminded by Zero that he wont allow her to become a vampire. She finds his look menacing and it hurts her, but she finds she doesn't feel scared. Yuki collapses later at a picnic with Kaname and is laid to rest in her bed, with Zero at her side watching over her. Ichiru warns Zero not to fall in love with Yuki.  When Zero returns after dinner to check on Yuki, she is awake and having a terrible hallucination. He asks if she's alright as he enters the room and is suddenly pinned to the floor by her. Yuki strangles Zero and he allows her to willingly until she calms and returns to her senses somewhat. She questions why he isn't fighting back when she moves her hands away and he reminds her that she can do what she wants with his life. Yuki smiles at this and tells him that it's she who he cannot escape from. She admits that protecting Zero and becoming his ally was all done selfishly so she wouldn't have to face the past she'd lost, because she could focus on being indispensable to Zero instead. Zero tells her that, although it sounds like she needs him, she needs Kaname. Yuki gets up and brushes the incident off, assuring Zero that she's fine and ushering him out of the room. In reality, though, the room is still bloodied and Zero is unable to stop Kaname from spiriting her away.
Although Yuki didn't want Kaname to be ashamed of her, she acknowledges that she wanted to save Zero and keep him alive, even if she was hated or shunned by him. She acknowledges that she has hurt Zero many times and that her current situation was her punishment for doing so. To Zero's horror, Yuki awakens as a Pureblood vampire with all of her memories restored. She reveals Kaname as her brother, although he later tells Zero otherwise while she is unconscious, and apologises profusely to a despaired Zero who has his gun pointed at Kaname. The fully awakened Yuki, after being left alone by Kaname, smells blood and is relieved that it does not belong to Zero. She knows, though, that she hasn't a right to worry for him anymore. Despite this and the protests from Hanabusa and Akatsuki Kain, Yuki makes the move to go and visit Zero. She cannot knock his door once she's there, but Zero senses her presence and points a gun to the door. Furious and betrayed, he calls Yuki an arrogant Pureblood who toys with people. She agrees with him, stating that the human Yuki has been devoured by the vampire inside her. Although she smiles while saying it, Hanabusa witnesses her crying afterwards.
Zero is detained by the hunters meanwhile and is shown to be thinking of Yuki smiling. He finds himself unable to calm down or silence the thoughts in his head about her or the fact that he can feel both of the Kuran siblings in his bloodstream now she has been awakened. When he senses Rido Kuran's presence he resists the thought that Yuki is different from the other Purebloods. Kaname taunts Zero, knowing that he will aid Kaname because it's for the sake of Yuki - who even as a vampire he won't betray. Later, as Ichiru is dying in his arms, Zero begs for him not to die because he doesn't want to lose anyone else. Ichiru's final wish is for Zero to live on and do what he cannot. Yuki and Zero reunite on the battlefield, and even though Zero declares Yuki his enemy she reminds him that she made up her mind a long time ago and she's on his side - even if they are enemies. Although Zero tries to stop Yuki from assisting in his battle with Rido, even going so far as to throw her from the roof, she ultimately helps him to defeat Rido. Once the dust clears and Yuki asks if Zero's alright, he coldly warns her to stay away and raises his gun at her. He says that he's sick of everything and the only way to be forgiven for his own sins is to eradicate the Pureblood race. However, despite his demeanour he assures Yuki that it's not her fault. Yuki responds by raising Artemis at him, stating that she cannot die yet.
Zero finds that he cannot pull the trigger at Yuki, for the finger on the trigger and the trigger itself feel weighted down. He understands that even if he wanted to end things, he's still attached to the past. He's still attached to the human inside Yuki, though he doesn't want to remember her any longer. He reminisces on the times when she'd look after him while he was in great despair, clinging to the warmth of her palm. In those memories he expresses irritation at Yuki's relationship with Kaname and how it could have shaped her into the kind girl who'd pressed her palm to his head on those nights. He remembers being scared and having her there embracing and comforting him. Though he knows he shouldn't have yearned for Yuki's arms, they held him back anyway. That Yuki who looked at him with support and strength still does so as she stands as a vampire in front of him. Angrily, Zero questions why she wont kill him. Kaname arrives and a violent confrontation between him and Zero begins over Zero pointing his gun at Yuki, even though Kaname himself remarks that Zero may not have truly intended to kill her. Yuki intervenes and is ultimately left to say goodbye to Zero.
Realising that the Bloody Rose is taking Zero's blood, Yuki pries it from his grip although it causes her pain. Zero glares at her, and she begins to back off once she's sure he's fine. However, Zero pulls her into his arms and holds her. He asks if the Yuki he knew is there still and she admits that she is, but she may disappear forever soon. Zero reveals to Yuki that it's only her blood he has ever wanted to the point where only devouring her would completely satisfy him. He then proceeds to drink her blood and kisses her. Before letting her go, he makes sure she is no longer scared now her memories are returned. He then tells her to go and declares that he'll kill her should they meet again, to which Yuki responds that she'll keep running if that will give him a reason to live on. The two then part ways entirely.  After leaving Zero, the shock of the evening's events finally catches up to Yuki as she realises the implication of Zero's kiss. She falls to her knees and cries, not wanting to be Zero's enemy, and apologises for the fact that she is a vampire and therefore is not right for him. Knowing that her true self will not ever change from now on, she finally resolves to lock away the pain in her heart and goes to Kaname's side. She gazes at the picture of her and Zero in her room before leaving, only to see Zero one last time carrying his brother's corpse. Finally, she goes with Kaname to the Kuran Mansion. While on the way there, Kaname lets Yuki know that he's aware her heart is half connected to Zero and she doesn't have to hide it. Kaname also tells her that vampires can only have their thirst quenched by drinking the blood of the one they love.
After a Year
After a year has passed Zero is revealed to be a fully-fledged hunter, although he still attends classes. He reveals to Kaien that he becomes uncontrollably thirsty at night and only hunting can distract him from madness. Kaien witnesses Zero scarfing down blood tablets and admits that although he's not falling to Level E, he's not entirely sane or insane. While confined to the Kuran Mansion for a year, Yuki is still thinking about Zero. She's shown to be suffering from thirst, too, but refuses to use her fangs to drink Kaname's blood. While at school, Yori asks Zero if he'd hurt Yuki despite her having done nothing wrong. Zero does not reply to her. Meanwhile, Yuki is thinking about her vow to run from Zero forever, or at least until one of them dies. It is revealed that she's suppressing the vampire inside her while fearing the eternity she faces and she is lonely. She reminisces about her last day with Zero and her heart's attachment and begins to thirst uncontrollably. Kaname reminds her soon after about vampires thirsts being quenched by the ones they love, and she acknowledges that her attachment to Zero means her thirst will never be entirely quenched by Kaname.
An upcoming soirée means that Yuki and Zero will be reunited. Kaien and Zero discuss this and Zero states that he'll kill her when he has a legitimate reason to do so. Kaien vows to protect her from Zero even if it's wrong to do so, because they are both important to him. While getting ready, Kaname wonders if Yuki is worried about Zero's presence. Yuki responds that she knows Zero will focus on his work. At the soirée, Yuki and Zero lock eyes for the first time in a year. Zero intervenes when Sara Shirabuki comes too close to Yori, who was snuck into the party by Kaito Takamiya. Yuki finds the three of them and places her hand on Zero's arm, requesting he let go of Sara. Zero tells her coldly not to touch him, and she replies that she'll let go of him once he lets go of her. Zero lets go of Sara and drags Yori away. Behind closed doors Yuki thinks about her first touch with Zero after a year and holds her hands close to her chest.
Zero is forced by Hanabusa and Kaito to accompany Yori as she goes to visit Yuki for an hour. However, he refuses to see Yuki after accompanying Yori as an escort to Yuki's room, stating he has no reason to do so. This seems to frustrate Hanabusa. After the two leave, Zero looks down at the arm Yuki touched and finds his veins pulsing. After a crime scene is uncovered and Yuki tries to involve herself, Zero coldly remarks that it's not a game and tells her to stay out of it. Yuki argues that she's not the useless Yuki from before any longer and wants to help. Ultimately, however, she is stopped by both Zero and Kaname. While discussing the crime with Hanabusa she finds out that it was easily resolved and immediately thinks about Zero. Then, after Kaname leaves for the day and leaves her Artemis to her, she reminisces on her vow to Kaname but thinks of Zero while doing so. Kaito finds the gun Zero had given Yuki under a pillow in his room and demands to know more about it. He reveals that, although the person holding that gun has gone and left the gun in his dorm, he keeps it with him to calm him down.
While visiting Ichiru's grave, Zero thinks about Yuki and begins to thirst. Coincidentally, Yuki is on her way to the cemetery to visit Momoyama, the former housekeeper. She is suddenly attacked by the Pureblood Toma and is severely wounded. Zero felt Yuki's presence and made a move to find her. He suddenly was greeted by the strong scent of her blood and remembered an old feeling. The scent made him dizzy. She notices Zero is there and tries to gain composure, greeting him with a smile. Zero pulls out his gun, alarming Hanabusa, but it's revealed that his target was actually Toma. As soon as Toma leaves, Yuki collapses in Hanabusa's arms. Zero lifts Yuki over his shoulder and carries her to a society hideout with Hanabusa in tow. Through what consciousness Yuki has, she realises her body is swaying and she can recall memories with Zero's scent. She berates herself for greeting Zero in such a way. The more Yuki awakens, the more intensely she can hear Zero's blood pulsing and his scent strengthens. She pulls herself up and buries her face in Zero's neck, licking there. Before she sinks her fangs in, she comes to her senses and meets Zero's gaze. Zero remarks that she's lost a lot of blood, but lets her down at her request. Yuki thanks him and apologises for what she just did, then runs away and retreats home with Kaname's familiar.
Yuki is punished by Kaname but praised only for not taking Zero's blood. Hanabusa, who is now in custody, is prompted by Zero to be upfront with what he's thinking of saying. Hanabusa states that if he were Zero, he'd keep trying to steal Yuki away from Kaname no matter how many times it took. Zero does not respond to this, but he meets Hanabusa's gaze. Hanabusa later tells Zero that he didn't mean what he said about stealing Yuki away, he just said it out of annoyance. Zero responds in anger, grabbing him by the shirt and demanded him to stop forcing her into his life, because it's not like Yuki herself asked him to do so. Hanabusa agrees and is let go, but he remarks that Zero should start acting like Yuki's enemy if he's proclaiming to be it. Zero agrees and leaves.
As Yuki reaches for Kaname, Zero grips Yori's wrist - waking from what appears to be a nightmare in the stable. It's implied by Yori that he believed it was Yuki's hand reaching for him as he slept. Zero recalls the injured Yuki from the other day and it disturbs the horses. Although he assures Yori he's fine, he's shown gripping his neck with thirst. After Kaname 'murders' Nagamichi Aido and shortly before Yuki is taken into custody, Yuki compares the situation of separation to that of hers and Zero's. It was again something she could do nothing about for something she could not change.
New Leadership of Vampire Society
After the death of Hanabusa's father, Yuki is taken into custody and passes by Zero on her way to be questioned. When Kaito brings back a child, Yuki touches her head and absorbs her memories. She sees the incident as it happened through the child's eyes, watching as Zero rescues her from a vampire. Worried, she asks where Zero is, but Kaito refuses to tell her. This leaves her visibly upset, and she resolves to set out and punish the vampire evading Zero's capture. She stops at a bar and finds the culprit, and knocks him out during her pursuit. Zero is shown waiting outside the door and states that he was his prey. Though Yuki coldly replies that he shouldn't have let him escape, inside she's wondering if he's okay. In response to her, Zero uses Kaname's crimes as means to hurt her pride. Zero leaves the culprit vampire for Yuki to hand over and Yuki later decides, even though it'd make Zero angry, to reinstate the Night Class.
After a meeting with the students, Yuki and Zero stand a few feet apart in front of a closed door. She questions what is on his mind and states that she knows he thinks what she's doing is meaningless make-believe, that vampires are beasts in human form. However, she disagrees as she always has done. Yuki later pleads with Kaien to not allow Zero to patrol the Night Class, fearing Zero will descend to Level E. While thinking about this, she recalls the memory of him confessing his desire for only her blood, but shrugs it off. She continues to ponder over this as she lies in bed, assuring herself that his emotions of the past have gone. When she leans up, though, she finds herself thirsting. Yuki later helps the hunters with her students to track down law-breaking vampires, much to the dismay of Kaito. Zero and Yuki exchange a gaze from a distance, but he ultimately turns away and leaves with Kaito.
During a confrontation with a suspect, Yuki is threatened by the suspect's girlfriend. Zero appears and guns the suspect vampire down, much to Yuki's dismay. Zero berates her softness towards vampires and grabs her wrist. He tells her that if she's against what he does, she can still use the bracelet to tame him. Initially saddened, Yuki snatches her hand away and replies that there's no need unless he became a Level E. After he leaves she clutches her throat, thirsting. Zero later finds her in her room taking blood tablets. He tells her Takuma wants to speak with her and leaves. Once outside, Zero grips a tree and clutches his throat, thirsting. Sara pities Zero's hunger. Maria, meanwhile, makes an observation to Yuki about the change in her relationship with Zero. She asks if Zero isn't needed by her anymore and states that she may take him away from her.
Yuki responds that although Zero is not unnecessary to her, they are enemies. It's the only response she can give, because they are enemies regardless. She spots Zero carrying Maria and hides, even though he can sense her presence. She reminisces over her admission to Kaname about Zero's attachment in her heart, knowing that she can't drink his or Kaname's blood despite her thirst. Zero passes her by and he warns her to stop playing school if she cant tame the vampires. She admits that they're difficult to handle, and it would be easier to give up but she can't do that. Suddenly, she confesses that she wants her and Zero to talk like they did before. Zero redirects her admission as a sign of thirst and takes her to the woods. He draws blood from his wrist and offers it to her, threatening to shut down the Night Class if she continues to lose her courage. She refuses and he declares he'll end it rather than have it run by a starved vampire. Yuki tells Zero that he should respect himself more, and laments over their constant need to hurt each other to move forward. Finally, she takes Zero's wrist with both hands but instead lunges upwards to his neck.
The pair are next seen sat beneath a tree. Yuki licks Zero's neck but pulls back, leaving a trail of saliva. Zero questions if she's stopping, and she assures him that she isn't. She gazes directly into his eyes, wanting to take a good look at him before she drinks his blood. She says that she's not doing this because of Zero's persuasion, as they both share a common interest. She desires his cooperation and in return she'll be focused - admitting that she can't get past her thirst at that time. Yuki comments on Zero's calm demeanour, admitting that she's very nervous and requesting he keeps his mind clear. Zero replies that he has nothing in his mind he doesn't want her to see, for his old feelings for her have gone - only fragments inside him force him to remember her existence. Contrary to this, a human Yuki is sat on a tree in Zero's mind and assures Yuki that she's not his greatest fear. Zero scolds her for prying into his mind and she finishes drinking from him. She makes a teasing remark about him being a peeping tom, but assures him that she didn't see much. Though she wants to ask about his own thirst, she resists and thanks him instead. However, inside she realises that drinking Zero's blood immediately cooled her head.
During her following encounter with Zero at school, Yuki and Zero have a very brief conversation regarding Day Class students wandering. She pats his shoulder in a friendly manner and smiles at him, saying she'll leave the duty to him. She then dashes away and slumps against a wall once out of sight, worried that she acted strangely in front of him. Reassuring herself that she just needed to start over from scratch, Yuki hurries to class. She tries to protect Zero from the hunters during a meeting in the woods, but is pushed aside by Zero himself, scolding her for acting as his master. Yuki finds his behaviour to be mean even after all this time. As dawn is breaking she's confronted by both Kaito and Zero and they discuss Kaname's plans. Yuki is incredulous at Kaito's heartless attitude, to which Zero responds that it's because they know Purebloods are nuisances.
Kaito leaves and Yuki admits that while she wants to stop Kaname she cannot promise anything. She acknowledges that most hunters want all Purebloods eradicated, including Zero - even if that means her death too. Yuki pulls Zero beneath a tree so they can be shaded from the morning sun. Zero makes a move to leave if she's done talking, but she continues. She acknowledges that Zero was only acting coldly to protect Yuki from the hunters. She believes that he doesn't want all Purebloods to die due to his kind nature, being one of the kindest people she's ever met, and she admits her worry for his heart's welfare in the process. Zero presses his gun to her head at her words, and she encourages him to pull the trigger if she's wrong. He does not pull the trigger, though, and Sara interrupts them.
In private, Kaito reveals that the hunters are using Zero and Yuki's feelings for each other as insurance for their own benefit. After all, Yuki is a useful Pureblood who can wield the weapons of hunters and they need her on their side, so her relationship with Zero is of convenience to them. Although Zero told Yuki to meet with Kaien at once, she does not, and so Zero catches up to her and questions her for not seeing him. He then delivers the message Kaien wanted to give Yuki, one that reveals Kaname was responsible for the death of Ouri at the soirée and also of Hanadagi - and that Sara will be next. Yuki thanks Zero for the message and wonders if she's just a piece on Kaname's chessboard. Before she can leave Zero grabs her arm and the two look at each other. She smiles, confused, and he lets go of her.
Zero accompanies Yuki, much to her dismay, to retrieve Sara's blood tablets from the Night Class students. However, when she takes them she's attacked by the students and she throws the tablets to Zero. The students pierce Yuki's arms and Zero raises his gun, but Yuki demands he doesn't shoot. The students regain their senses and she thanks Zero for his help. Zero, however, is visibly angered and warns her not to come near him. He leaves Yuki alone, her arms bloodied. While Yuki is on her way to confront Sara, she is stopped by Maria who tells her she can't help Zero's hunger. Yuki acknowledges that Zero is starving, but states that she wont go to him herself out of respect for him. Zero arrives as Yuki is met suddenly by Hanadagi's servant, and she recognises him as being in Sara's room last night. Zero addresses Yuki in a way that he hasn't in a while and warns her that he wont allow her to do anything to Sara. Enraged, the servant girl lunges for Zero but is quickly knocked unconscious by his hand. After Maria takes the servant away, Yuki apologises and promises to go after Kaname once she's done - believing him not to be so tainted after all. Zero suddenly chases after Yuki and shoves her against the wall, pinning her there. He calls Kaname tainted in every cell and reveals angrily to Yuki that Kaname was responsible for the slaughter of his family, stunning her.
A form of Kaname arrives, although it's not the real him, and Yuki steps forward. However, Zero grabs her arm so tightly that it hurts her, preventing her from getting closer to Kaname. Zero reveals that in his heart he'd believed Yuki and Kaname would be together and walk the same path, and Yuki acknowledges that Zero has always wished for Yuki's happiness above all else. She initially demands he tell her what Kaname is hiding, but then eases up and assures him that he doesn't have to. He doesn't answer her, instead directing questions at Kaname that confirms he was indeed responsible for everything that had happened to Zero those 5 years ago. She learns that Zero was Kaname's pawn who was made into a weapon through destroying his livelihood. Zero's rage begins to take over through Bloody Rose and Yuki intervenes, taking his arm in one hand and resting her other hand on his head. She looks up at him tearfully and he pulls her into an embrace. Zero tangles his fingers in her hair for a moment before pushing her away. While Yuki is sure Kaname is doing these things for Yuki's sake, Zero insists that Yuki is wrong and shouldn't cry for Zero.
Before Zero can back away entirely, Yuki grabs his wrist. She says she'll go after Kaname and so he needs to protect Sara. She assures him she wont lose control and that she's not worried about Zero. She lets go of his wrist and they part ways. Zero reminisces about the human Yuki who had died the day the vampire had awakened inside her, and that he had kissed her corpse farewell on the battlefield. He questions why it was that he wished for Yuki and Kaname to be together - the Kaname who had destroyed his family and made it so that in the end his own brother lay lifeless in his arms. During a confrontational fight with Kaname, Yuki is put under an illusion by Ruka Souen. In the illusion Zero asks why Yuki wont abandon Kaname after all he's done to him and shoots her through the head. However, Yuki realises quickly that it's an illusion as she knows Zero would never blame her for Kaname's actions. Following another encounter with Kaname and a failed capture, Yuki stares at an injured Ruka who is in Akatsuki's arms. Zero pokes the back of Yuki's head and the two continue on their pursuit of Kaname. Zero carries Yuki into the association due to the traps being active. Kaname is confronted by the pair and Yuki is reminded of the deep dark forest she and Zero are kept in. Yuki cuts her hair short and apologises to Zero, vowing to be beside him from now on. She believes inside that they both will find a way out of the deep dark forest someday.
Following the death of Sara and Kaname's escape, Yuki is seen kneeling on the ground. Zero approaches and pats her head, and she takes his hand and pulls herself to her feet. The two decide to go after Kaname together. Yuki acknowledges that Zero is needed where he is, and shouldn't go with her - calling him softhearted. Kaito confronts Zero as she says that and threatens to arrest him for treason. Zero punches Kaito in the face and states that he'll go no matter what. Kaito reminds Zero that Yuki is a Pureblood, a monster that dragged their loved ones into darkness. Zero comforts Kaito but doesn't change his mind regardless, and Kaito seems to understand why. Suddenly, Kaito punches Zero in the face in return for Zero's punch and forces the pair of them out of his sight. The two travel together on a cart, neither saying a word to the other, and walk at a distance from each other. Finally, Yuki turns and questions why he hasn't spoken. Zero reminds her that she wanted to go after Kaname and she can't dare to withdraw now. Yuki in turn reminds him that he'd injured himself and that he needs to stop being reckless if they are to work together. She visits the Kuran Mansion and brings up the topic of their relationship, something Zero clearly doesn't want to discuss. She tells Zero that she can't spend her life with him, because she belongs to Kaname. Zero knows this, she's betrothed to the one who ruined his life, but she also saved his own life. He takes Yuki's wrist and asks her if their meeting was orchestrated just like his early life was - if their thoughts and feelings for each other were just an orchestration too. He flicks Yuki's head before she can answer and reveals that he wants to know the truth about it. She understands that this is not only her journey, but Zero's too, and the last one they'll take together. His words pierce her heart.
Yuki continues her visit of the Mansion and finds Zero dozing by the entrance on her way back. He wakes to find her reaching for him, and she quickly moves her hands behind her back. They leave and Zero tells her she could have stayed longer. Yuki admits to Zero that not all of her memories in that place were good, and she wants to hurry. Zero responds by lifting her up and jumping off of a bridge. He races down the mountain with her in his hold and tells her to be quiet as he knows she's been giving blood and is therefore not at her best. Yuki thanks him for looking after him but reassures him that she's taking tablets and looking after herself. She's unsettled by Zero's treatment of her being so familiar, as she doesn't know how to approach him the way she used to. She realises he's asleep on the train as she's taking tablets and she pulls down the shutter. Zero awakens to find her straddling him, one hand gripping his injured wrist and the other clasped around his face. She questions how long he's been going without any blood and licks the drop of blood that falls from his cheek. Her neck is bleeding from a self inflicted wound and she invites Zero to drink her blood. Zero shoves Yuki away from him and she bumps into the opposite seats. Yuki seems indifferent to his reaction and continues to question him and how he has coped for so long despite being tolerant of the tablets. After a momentary silence Zero reveals that until he was watched over by Kaito he'd feed from the prey of those he'd hunted, even though the blood was tainted and disgusting. The pair speak out in unison, surprising each other, but Yuki isn't sure how to finish her sentence. Zero tells her it's nothing to do with her and she apologises, letting the topic drop. The two settle down and nap while Yuki laments that the two have masked their hearts from their true feelings.
Upon arriving at the residence of Isaya Shoto, they are greeted by a servant who delivers an invitation to the masquerade soirée taking place that night. Yuki dresses for the occasion and she watches Zero patrol the area with Isaya. Isaya asks her if she's going to dance with Zero, but she recalls that Zero told her once he couldn't dance. Not only that, but he is a hunter and she is a Pureblood. After dancing with Isaya, Yuki goes out to the balcony. Zero finds her there, taking her by surprise. Before she can speak, he places his fingers on her lips, reminding her that the two are supposed to hide their identities while masked. Yuki puts her mask back on and greets Zero, acting as though she doesn't know him. She tries to shrug it off as a joke but Zero holds his hand out to her. She takes it and they dance together. Yuki remarks that she didn't know Zero could dance. Zero tells her that she looks like a girl who died a year ago that meant a lot to him, and in return she tells him he looks like a boy she worried about and wanted to protect but hurt instead. However, she says that he couldn't be that boy, because that boy would never dance with a vampire. The two continue to dance as old memories resurface and Zero leans towards Yuki. She wonders why it had to be this way with the two of them. Leaning up on her tiptoes to reach, the pair kiss. She admits that Zero is still the boy she cherishes and, in fact, loves. She acknowledges those feelings inside her are real. The mask slips from her face as she realises Kaname witnessed their kiss.
While chasing after Kaname, Zero pulls away his own mask and it falls to the floor, reminding the two of their kiss. Despite their best efforts, Kaname once again evades capture. The next day Yuki comes to get Zero as he's getting ready. They converse about Kaname's conversation with Isaya and the night before in general. Yuki recalls a memory of the ball back in the Academy to Zero and then reveals something she's wondered about since the masquerade last night. She wonders what would have happened if there were no vampires and they'd met as humans. Zero would probably be an upperclassman in that reality, but he would likely still not get along with Kaname. She indulges further in the fantasy, creating a scenario between them on the night of the ball if he'd came in bloodied, and wondered what would come from that encounter. She wondered what she'd have done as a human girl of 17 with Zero in that life instead. Zero cuts her off when he opens the door, berating her for her stupidity. He reminds her that Kaname was the cause for everything, so without his influence the two would never have crossed paths. Before he can move past her, Yuki pins Zero to the wall and frantically repeats his name. She runs a hand through his hair and opens his jacket, then leans up and bites his neck. Zero quickly realises she's trying to take his memories and struggles against her, forcing her to use her bracelet and subdue him. She explains that taking the memories away will free him from her and take the pain away. Zero cries out that he'll never forgive her, and she apologises to him but continues on anyway. She tearfully reveals that it's the only way because she needs to turn Kaname into a human.
When Zero next awakens, his memories are completely gone. Yuki is watching over at his bedside, and asks if he's thirsty. Confused and angered, Zero points his gun at her head and demands she leave. Satisfied that he's forgotten her, Yuki does as he asks, calling him a softie for not pulling the trigger even without his memories. She's confronted by Kaito in the hallway, and he disgustedly remarks about Yuki stealing something precious to Zero, twisting his life around and acting indifferent about it like a true malignant Pureblood. Yuki smiles sadly at his words and leaves. Zero enquires about Yuki to Kaito, because he believes Purebloods to be a nuisance. Kaito asks if Zero's still craving blood, and Zero admits that he can't understand why his thirst was so rampant before. After reuniting with Kaname, he confesses that he should have entrusted her to Zero sooner. This upsets Yuki, who is visibly frustrated with him using Zero as a pawn. Kaname admits that Zero falling for Yuki was not apart of his plan. He also admits that he left her side because he knows his love won't make Yuki smile from the bottom of her heart. Zero is visibly struggling with the loss of his memories, but he shrugs it off when Kaito questions his state.
Kaito and Zero arrive to protect the Kuran siblings inside their Mansion until the furnace is ready. Yuki senses Zero's presence and refuses to greet him. Kaname lifts Yuki from the bed and carries her into the sitting room, where he drops her onto a seat despite her protests. Reluctantly, Yuki apologises for her rudeness and expresses gratitude to Zero for protecting Kaname. She tries to leave but is stopped again by Kaname, who forces her to sit and have tea with him, Zero and Takuma. Zero notices Yuki's discomfort and suggests Kaname let her go. When he goes to leave, Kaname takes hold of Yuki and bites her neck in an attempt to rouse Zero's memories. Yuki struggles and slaps Kaname, demanding him to stop dragging Zero back into their problems. She tells Zero he can leave, but he's under orders to stay and protect Kaname. Kaito scolds Zero for allowing the Kuran pair to manipulate him and acknowledges that, although it'd be better to be without memories, it was a cheap way out for Zero to accept his memory loss. He encourages Zero to remember quickly, so that he can prove to Kaito it wasn't wrong for him to forgive his enemies.
Zero thinks over what Kaito had said to him, but cannot understand what he means, just as he cannot understand why he's entrusting his back to Kaname when he despises all Purebloods. Yuki, in particular, he comments is odd. He finds she's not like a Pureblood at all, she presents herself apologetically to Yori. He knows he never wants to see her with such a look on her face, but he cannot understand why. Even Ichiru's death and last wish has lost its meaning where he knew there once was one. Zero brings Isaya to the dungeon and Yuki is taken from Kaname's side to be turned into a human. As Isaya prepares to turn her, the memories inside Zero of a girl he wanted to protect begins to stir. Even though she's being turned, he doesn't feel happy with there being one less Pureblood. Her anguish ignites something inside and he pulls her by the arm away from Isaya, slamming her against a tree and pinning her there. He stares at a tearful Yuki, someone he describes as a muddled, kind yet selfish stranger. His memories flood back and he announces that she's Yuki, the girl he wanted to protect always - even though she never allowed him to. Worried, Yuki asks if Zero has remembered everything again. Zero, frowning, tells her he remembers what he'd forgotten - that she was the one who took the memories precious to him. Before she can get away he grabs her arm and pulls her into his embrace, tilting her head with one hand. He declares he wants his memories back and bites Yuki, taking her hand in his when she goes to lift it. He recalls Ichiru's last wish to Yuki and confesses that he was afraid to face his true feelings for all of that time, but he wont make excuses anymore.
Kaname throws his heart into the furnace and both Yuki and Zero are too late to stop him. Yuki cries in Kaname's arms, wishing she'd never been born. Kaname tells her he has no regrets. Zero tells Kaname he'll never forgive him for placing sorrow in Yuki's heart. Kaname smiles and tells him that's fine, then embraces them both. He confesses that the pair were always so radiant that he had to shield his eyes, and he knew all along they should have been together. He gives blessing for them to be together as his last wish, and passes away in Yuki's arms. After the battle is over, Kaname is kept encased in a coffin of ice. Zero watches Yuki as she stares at the coffin and tells her he won't run away any longer, and that she should think about what he said also. He knows that she's blaming herself for everything currently, though. However, Zero embraces Yuki from behind and pleads for her to come with him after everything is over - no matter how long it takes, so long as it's before thirst turns him to dust. Yuki blushes tearfully, but doesn't respond. After a thousand years, Yuki is shown standing at the Kiryu gravesite after Zero's death with the Bloody Rose fragments in her hands. She recalls that she and Zero had fought a lot, but Zero had brought a lot of happiness into her life. She then gives her life to Kaname and turns him into a human, and he awakens to Yuki's children - one fathered by Kaname and the other by Zero.
In the AnimeDuring the last episode of Vampire Knight Guilty, the parting of 46th Night is very different, instead of biting Yuki, he asks her to drink his blood to prove that she really has become a vampire. Zero is not surprised, but instead vows that one day, he would kill all Pureblood vampires, including Yuki.
The show ends with Zero remembering spending guardian duty with Yuki as he stands before the gate of the Night Dorm. He sees the mirage of Yuki yelling at him to hurry up and help her, he begins to come towards the mirage until he finally regains awareness of his surroundings. The last scene is Zero pulling out Bloody Rose whispering her name, the cutscene changes to Yuki sullenly walking with the other Night Class students towards their new home saying, "I know Zero" or in other versions "Farewell Zero."
Zero's tsundere and aggressive nature keeps him from befriending people, ensuring that Yuki is the only one close to him. Yuki's sunny, stubborn, and silly nature allows her to ignore Zero's aggression and rudeness overriding his desires with her own, inadvertently bullying him. Zero's affection for Yuki causes him to fiercely protect her and be easily directed by her. His nature is primarily shy and he does not communicate his feelings towards her, though he expresses frustration in the form of bullying her at times, causing Yuki to think he didn't like her.
Zero began developing feelings for Yuki when she took care of him during dark times after his parents died, it is thanks to Yuki that Zero did not commit suicide. It becomes noticeable within the beginning of the manga that he holds hidden feelings for his fellow guardian. Whenever Yuki makes a comment on not all vampires being bad guys and sticks up for him he blushes to which he turns his head away so she doesn't notice. When Yuki gave Zero one of the few chocolates that turn out edible for Valentine's Day he eats the chocolate and despite disliking the flavor he is shown blushing to receive chocolate from her. At the beginning, Yuki holds no hesitation in dealing with Zero whenever he walks around shirtless or acts cold towards her. She responds heatedly to these actions and while she looks embarrassed in front of other males who show flirty mannerisms with her, Aido and sometimes Kaname, with Zero she is much more relaxed. She often teases Zero whenever he starts acting moody and isn't hesitant in reprimanding him for being unfriendly to the Day Class girls.
After Zero turns into a vampire, despite her fear of the creatures who almost caused her death ten years prior, she reminds herself that despite what people say Zero isn't a scary person though he tries to be. Whenever Zero takes blood from her to ease his hunger she becomes curious as to why he desires only her blood and almost constantly hungers for it, this question often bothers Zero and he tells her not to worry about it (due to his refusal to admit he's becoming the creature he hates and his hidden feelings for her).
Not until 20th Night, when Zero asks Yuki why she does so much for him, does Yuki begin to actually think about their relationship and how she views Zero, though no conclusion is shown from this. Yuki was almost oblivious to Zero's affection for her until 25th Night after he almost kisses her, it is speculated that from this point that she begins to notice Zero in a different manner. However, she is still uncertain about his feelings, and chooses to not look too deeply into things as of right now.
On the 35th Night, Yuki's origins as a Pureblood vampire are finally revealed as Kaname awakens the sleeping princess. Yuki has just remembered her heritage as a Pureblood Princess when Zero comes across the two of them due to the smell of Yuki's blood. When Yuki reveals the truth, Zero is clearly distraught, torn between shooting them or not. Kaname takes an unconscious Yuki away in order for her to finish the process of turning into a Pureblood vampire, while Zero numbly absorbs the information of Yuki's origins as a creature he should despise. When Yuki fully turns into a Pureblood vampire and recalls her past on the 36th Night, Kaname leaves to take care of business when Yuki smells blood. She is horrified, though is relieved when she realizes it's not Zero's. After realizing how relieved she is that he is safe, she is surprised with how concerned she was.
Following Zero's kiss in 46th Night, Yuki is finally made aware of Zero's feelings for her. Yuki confirms in 47th Night that she finally understands his earlier overtures, but due to Zero's hatred of Pureblood vampires, Yuki knows their relationship has changed. Zero tells her as she begins to depart with Kaname that he will still continue his quest to eradicate all Pureblood vampires; Yuki comments that she understands and that is why she will become his enemy so he will always have an enemy to go after. After Yuki and Zero reach their agreement, she wanders off and breaks down sobbing since she does not wish to become his enemy, and now realizes his true feelings for her. However, she bottles this up since they both are enemies and as a Pureblood vampire, she cannot break down sobbing over a lost ally.
Yuki finally admits she feels something in return for Zero in 51st Night. When Kaname asks why she cannot drink from him, she reveals that she cannot be fully sated by him because a part of her heart is still attached to Zero. She does however feel it is unfair on Kaname and should not be allowed to stay by Kaname's side. At the ball, Yuki continues to be protective of Zero's feelings and notes in the party how Zero perceives others like Sara as his enemy and she later notes his pain on seeing the vampire hunter girl having been turned into a vampire. She reveals to feel awkward with how indifferent his interactions are with her now.Following Yuki's revelation of being a Pureblood vampire, Zero's feelings of anger have been more obvious than his love for her. After the year time skip, his love and blood lust for her is left ambiguous. Both characters avoid calling the other by the names they once so comfortably used. Despite Yuki's ambiguous feelings, their relationship has been reset somewhat from the comfortable friendship because of their status as enemies, Yuki's awkwardness is on display when during a coincidental meeting in 60th Night, Yuki greets Zero with a "Good evening" and mentally berates herself for being unable to respond better. Yuki collapses after an attack and Zero carries her to the Hunter's Association for treatment. She begins to regain conscience and almost bites Zero (whom, she says has a nostalgic scent and his blood smells desirable).She stops herself to see who she is about to bite, and is shocked to find herself face-to-face with Zero. She runs off after being confused on why she wished to bite him.
Zero returns to assisting Yuki subtlety after she rejoins them. He assists by nudging Aido towards Yuki. When Yuki states that Zero disagrees with her school plans, Zero declines to comment instead of agreeing, though he later insists that she is too soft and they are still poles apart on their stance on punishing vampires. When Yuki states she needs Zero, he fails to take it at face value and instead sees her as acting strange, so his response is that she must need blood. Contrary to all belief including Yuki's, he volunteers his own blood, showing that towards Yuki, his attitude has changed.
Yuki at first denies his offer for his sake, but finally relents and instead goes to bite his neck with her own fangs, despite him offering his wrist, echoing her earlier desire to take what she wants with her own fangs. She is first hesitant in taking his blood due to his animosity towards Pureblood vampires and position as future president of the hunter society; however, after drinking his blood she reveals that she feels sated and then wonders why his blood instantly calmed her.
After the incident, she attempts to act normal around him like she used to. When the vampire hunters approach them, Yuki instantly jumps in front of Zero, demanding what are they going to do to him, but they tell her that they are only there to announce to him that they are planning of going against Kaien's plan to stop Kaname. Later on, Yuki promises Zero that she will stop Kaname, and asks if Zero wants all the Purebloods dead, and he confirms it. She pulls him to a shady tree and tells him that she knows that he flashed a murderous vibe in front of the hunters to protect her, and if she is wrong then he should shoot her with Bloody Rose. Before Zero can reply, Sara shows up, interrupting their conversation.
When Yuki confronts two Night Class students about the pills, they bite her. Zero attempts to kill them, though Yuki tells him that it is okay. She throws the blood tablets to him, and the students revert back to normal. When they leave, Yuki thanks Zero for his help, however he tells her to stay away from him.
When Kaname reappears to kill Sara, Yuki and Zero join forces to stop him and resume their old behaviors as allies. During the fight, Yuki cuts off her hair to its former bob style to show Kaname she is disappointed with his change in character and is going to start taking action. After the haircut, she asks Zero if its okay for her to fight beside him, and he replies with a yes.
During the 86th Night, Kaname manages to escape, and Yuki tries to sneak off the next day to search for him by herself. Zero catches her during the act, which doesn't surprise her she admits, and says he is going with her so stop trying to sneak off. As they travel, there is a short interchange between the two that mirror Haruka and Juri's brief interchange about him bringing her an umbrella. While different scenarios and dialogues both situations appear similarly with Yuki/Juri annoyed at Zero/Haruka for following them. After reaching Kuran Mansion, Yuki tells Zero she cannot live with him and she belongs to Kaname. Zero sees through her actions, similar to her escape attempt, and explains that he wishes to learn about what was the purpose of his family being murdered and Kaname trying to develop a bond between the two. After listening to his reason, she tells him that she agrees it would be best if they both searched for answers. The chapter ends with Yuki saying this will be their last journey.
During the 87th Night, the two are continuing their travels to stop Kaname. Yuki is saddened when Zero will not enter the Kuran Mansion with her. When the two board a train, Yuki notices an injury on Zero and attempts to force him into drinking her blood. She states that it must be difficult for him not receiving actual blood since she has learned the feeling of being sated. He manages to shake her off and reveals that he drank blood from vampires he arrested on earlier missions, Zero and Yuki are shocked on this revelation and Zero resumes his cold attitude and tells her not to worry about him. Yuki decides to listen to him, but still questions over the things left unsaid between them. After the train ride, Yuki and Zero attend a masquerade ball at Isaya's place. During the ball, Zero and Yuki share a dance, during which the latter thinks about the feelings she has for Zero. Yuki finally confirms that she has also shared feelings for Zero but was oblivious to these changing feelings due to all the problems arising. In the midst of dancing, Zero and Yuki share a kiss as they remember time spent together, before being interrupted by the sudden appearance of Kaname.
In the 88th Night, after Kaname escapes, Yuki begins describing to Zero of an imaginative world where the two of them are not a Hunter or a Pureblood vampire, but humans.She continues by comparing how some of the events the two went through as Day Class guardians were changed and they lived in a world without vampires. She asks Zero what would happen to them if they were not in their current roles and Kaname was simply her brother. Zero dismisses her imagination and claims if all these events hadn't occurred then they would not have met one another so it is silly to dream up an imaginary world where they would be different people. At this point, Zero is revealed to have opened his heart into believing not all Pureblood vampires were evil thanks to Yuki, however Yuki still cannot move past her belief that their statuses will continue to haunt them. Yuki surprises Zero by using his bracelet against him to try taking away all memories of her which outrages him. He demands to know why she is doing this and Yuki explains that she did not want him to be burdened with the sorrow of her death because the only way to stop Kaname is by sacrificing herself to turn him human.
Yuki manages to successfully take away Zero's memories of her on 89th Night, after removing his memories he reverts to his earlier habits of threatening her when she asks him if he's doing okay. Yuki begins to speak to him coldly in order to try making him distance himself from her. Since Kaname still has not turned up, Yuki bides her time away at Cross Academy, now the Vampire Hunter Association Headquarters. After gloating at Zero being unable to pull the trigger at her once more, she wanders off into the hallway where Kaien stops her and asks her to come with him somewhere. Zero is finally able to return to hunter duties with Kaito, while Cross is talking with Yuki, Zero pauses to look at her wistfully. Kaito asks him what's wrong and Zero says that Yuki is different from other Purebloods and questions what is her relationship with the Hunter's Association since Purebloods don't usually work with the Hunters. Kaito asks if Zero's hunger has changed and Zero admits he doesn't understand why he isn't hungry anymore like earlier.
Kaien reunites Yuki with Kaname, where she learns Kaname never killed Aido's father. She leaves with Kaname and learns that despite learning his innocence he still plans to place his heart in the furnace. The two argue about Zero and Kaname is displeased on hearing that she removed his memories. He tells her that he should had turned her into a human sooner so that she could be with Zero, and she argues that he should have removed her memories of Zero to save her the pain. When Yuki asks why he still plans on becoming the parent to the furnace, Kaname notes that it's because she doesn't smile from her heart and hints that Zero is the one who manages to do this which she doesn't agree or deny. Since this may be their last night together, the two chose to make love to one another and the scene changes to Zero being placed with Kaito as the protectors of the Kuran Mansion since the Purebloods plan to assassinate Kaname.
On the 90th Night, Kaname learns that Zero has been placed as the Kuran Mansion's protector, he begins to toy with Zero's forgotten memories of Yuki, much to her dismay. Yuki stubbornly refuses to see Zero when Kaname tells her to come downstairs and have tea with them; finally growing fed up, Kaname has to drag her downstairs, while she argues the entire way down. When the company sits down for tea, the situation proves awkward since Zero is not sure why Yuki seems familiar and Yuki tries to stop Kaname from reactivating Zero's locked memories. Kaname begins to goad Zero into remembering Yuki by attempting to humiliate her in front of the hunter and begins drinking her blood. Finally feeling overly awkward, Zero leaves and Yuki slaps Kaname exclaiming that he should stop dragging Zero into their problems. She runs after Zero and tells him the mansion is no place for hunters to which Zero tells her to not concern herself with him since he is simply doing his job.
Right after Zero tells her to not concern herself in vampire hunter matters, Kaito and Zero begin surveying the Mansion's grounds. As they survey, Kaito scolds Zero for accepting what "that Pureblood" [Yuki] tells him so easily. He tells Zero to confront the two Purebloods and take back what is rightfully his [his memories stolen from Yuki]. While they are talking, the Purebloods' servants spring a surprise attack on the hunters, wounding Kaito in the process.
The battle continues in 91st Night, Kaito is wounded and Kaname has to step in and help Zero. The scene changes to the hunters taking the Kurans and Takuma to the newly arranged Hunter's Association [Cross Academy] for safety. Zero overhears Yuki asking Kaien if there is another way, besides the furnace, to stop the Purebloods. During their conversation Yori runs in and is overjoyed to find Yuki safe. Zero is surprised when Yuki tells Yori she needs to run to safety, Zero ponders over how she doesn't act like a typical Pureblood. Later, Kaname is placed in a cell beneath Cross Academy, with Yuki hiding as well. Zero approaches Kaname and comments how he senses a vampire who has given up living. He reminisces over Ichiru losing his life in the same place telling him to "live on and fulfill your goal" and someone else telling him to live. He is agitated over not remembering this mysterious person who helped him develop a need to live and questions over why he feels something is missing in his determination to carry out Ichiru's wishes.
After Zero's display of confusion, he is shown appearing before Kaname and Yuki who were resting within the cell. Zero tells Yuki she has a guest to which she shows confusion. Her confusion quickly changes to horror when she sees it's none other than Isaya standing before her. Yuki begins protesting to which Kaname stops her and says that even if she forgets him he will never forget her and releases her to the custody of Isaya with Zero as a witness/backup. Zero is bothered by her crying face as she is dragged out of the cell. Isaya continues yanking a protesting, distraught Yuki outside to the graveyard with Zero sullenly in tow. Yuki exclaims she doesn't wish to become a human now and there are still things which need to be done, and if she is a human she will no longer have these capabilities. The more she argues the more Zero's hidden memories of her begin to resurface. She keeps repeating over how she wishes to not become useless by losing her powers and this triggers something in Zero's conscience of a time she said the same thing as a human. Zero finally chooses to walk off since he doesn't have any reason in his mind for dealing with the Purebloods' issues any longer than possible. However, Zero grows more and more troubled with her dilemma. Finally, something within him snaps and he rushes back to stop Isaya's process for turning her into a human. He roughly snatches a hold of her arm and pushes her up against a tree. Yuki is still sobbing at this point while Zero is angered over why he can't get her out of his mind commenting over her being a kind, egotistic Pureblood. As he looks at her face his hidden memories begin to awaken and he yells that her name is Yuki and she was the woman he wished to protect, but she wouldn't allow him.
The next chapter [92nd Night], Yuki is speechless that Zero remembers her, she asks him hesitantly if he remembers everything. Zero replies that he remembers something important is missing and that he now knows for certain it's related to her. As Isaya leaves to help the hunters for the impeding battle with the Purebloods and their servants she tries to run after Isaya to help during the battle and avoid Zero from regaining his memories. However, her efforts prove futile as Zero latches on to her and says he is taking back what is rightfully his [memories]. Yuki tries to reuse the bracelet on him but he manages to hold off her hand and continues the process of regaining his memories by biting her and drinking her blood. Yuki, in her distraught, passes out and Zero holds the unconscious Yuki against him and says he was afraid to face his true feelings and he will no longer hide behind excuses [he doesn't realize Yuki hears these words before falling unconscious]. Aido reappears on the scene, and Zero hands Yuki to him saying he is going after Kaname to stop him. Zero rushes back to Cross Academy's main grounds and yells out for Kaname, saying he now understands that Kaname believes he doesn't have the right to be with her and that he should think about her feelings and not make her cry. Kaname appears before the Hunter and stands there catatonically as the hunters and Purebloods begin to battle with the Night Class helping the hunters. While dueling, the Bloody Rose begins to crack which springs Kaname into taking action. While the battle is commencing, Yuki wakes up as Aido is attempting to take her off the scene. She grabs a hold of his neck and begins to forcefully take his blood. Aido crumbles and Yuki runs off to change into the day class uniform and grab Artemis. In a comic moment, Aido has just finished gulping down blood tablets when Yuki reappears to drag him off to the battle grounds. When they get there, Yuki sees Zero warding off vampires, though continues looking for Kaname. The chapter ends with Kaname pulling out his heart.
The last chapter begins with Kaname throwing his heart into the furnace. Yuki appears shortly after and attempts to take the heart out to which Kaname stops her. Zero follows her and is shocked over seeing the state of Kaname and says out-loud Kaname shouldn't have done this. Yuki is crying over not being able to save him and if she wasn't born things wouldn't have turned out like this for him. Kaname hugs her and tells her she made him happy but he has to atone for the sins he helped cause. He further comments over being sorry for causing her light to damper- the smile they all loved- and for causing her sorrow. He continues saying how her light helped save him and a hurt boy [Zero] from their darkness. As he comforts her, Kaname looks back at Zero as he makes the comment on needing to atone, Zero looks at the man with sorrow filled eyes. Zero tells Kaname he cannot forgive him for causing Yuki to hold such grief. Kaname continues telling Yuki not to stop him and then calls Zero over, giving the two a hug as he gives them his blessing saying they should be together. Kaname slips into a slumber, Yuki runs off to challenge the remaining Purebloods in her grief while Zero begins to chase after her he is stopped by the new furnace taking away Bloody Rose. Yuki has just openly challenged the other vampires when Artemis turns into dust. Suddenly, Bloody Rose explodes from the furnace and starts to kill the remaining vampires. Cross Academy falls apart and the vampires begin to flee. Everyone watches in awe, Zero rides along the vines to appear before Yuki both share a look of determination.
Aido places Kaname's body into a frozen block of ice to prevent others from harming him. After the battle, Yuki goes to stare at his body in sadness. Zero goes with her and says that it's not because of solely Kaname on why he decided to no longer hide from his feelings. He continues telling Yuki he knows she's probably blaming herself for everything that's happened. He embraces Yuki and tells her to let go of her sorrow and that he will wait for her even if its a decade or longer until she can overcome her grief and tell him that she loves him. Yuki looks on sullenly as Zero comforts her.
The narration changes to show everyone's life affairs as Yuki tells the readers where everyone journeyed off to and Aido discovering a cure to change vampires into humans that Kaname had been working on. A thousand years have passed, and Yuki is shown placing flowers on the Kiryus' grave. She pulls out the remaining pieces of Bloody Rose that she kept as a memento and places it on his parents and brother's grave. While doing this she says outloud she figured Zero would have liked to be placed with his family graves. As she places the gun down she says to their graves that although they had several fights during their time together he still gave her a lot of happiness before smiling one last time. [Since Zero is a vampire his body had turned into dust so he does not have a grave to visit so the gun at his family's grave is in a way a funeral procession].
In the last scene, Yuki, with two teenagers in the background (The girl is Kaname's daughter while the boy is Zero's son or daughter), visit's Kaname's slumbering body stating the furnace had burnt out before giving her heart to revive him as a human. Her children state that she wanted to grant him the gift of seeing the world she saw as a human. Her final thoughts read, "May your thirst be quenched."
Vampire Knight Memories
The timeline in Memories starts when the main characters are in middle school, where Yori is the narrator. From Yori's perspective, we are told that Kaname is the reason Yuki does not have any friends, but she seems fond of him regardless. As this is revealed, Zero comes into the picture and Yori notices his look of 'irritation and something else'. She expresses excitement at watching the trio's relationship develop, but never imagined that things would end up as they did - with Kaname throwing his heart to the furnace and the events that followed soon after.
When Zero asks how much longer Yuki will stand at the ice coffin, as it has been two months, she lunges at Zero. He urges Yori to leave, and hidden from view she finds out that Yuki is starving for blood because of her pregnancy, something revealed by Zero to her. He reaffirms his position in her life, telling her that he is the only one who can be her partner and that she must stop looking as though she wants to be in the ice coffin with Kaname. Yori is shown to be shocked by this news, and reveals that Yuki left the academy shortly after finding out about her pregnancy. 
During the development of Aido and Yori's relationship, while Yuki is still pregnant, Zero informs Aido that he is, in fact, supplying both Yuki and her child with blood when visiting her. Yori reveals that Yuki disappeared for four years, staying instead at Ruka's summerhouse. She believes that, rather than doing it for the sake of keeping everyone safe, Yuki was doing this because she questioned Zero's reliability - despite his pledge to her before. Aido also questions Yuki's motives, because Zero would have been able to quench her thirst. Zero quietly arrives as they argue about his type of personality and why this may be off-putting to Yuki, and shortly after Yuki herself bursts into the room with her new baby.
With Zero watching in the background, everyone else gathers around and makes a fuss of the baby. Yuki then turns to Zero and thanks him for coming, noting that he is busy. Zero smiles slightly as he reaches for the baby, saying that she is the one who made Yuki attack him out of hunger. The baby, named Ai, grabs Zero's finger and Yuki smiles from the bottom of her heart once again. Zero also smiles warmly because of this, something Yori makes note of in Zero's last visit to her before her death. Following Ai's birth, Zero becomes a prominent figure in the lives of both her and her mother. Yuki comments on how that fateful night when she'd met Zero had left him with a purpose in his life for revenge only, and that his eyes had gleamed sinisterly. However, Ai's birth has given Zero lots of heartfelt smiles. He is shown holding and cradling Ai as Yuki smiles on, wishing that he would feel this warmth 'from now on and forever'.
When Ai is a toddler, it's revealed that Zero and Yuki still drink from one another. While Zero is drinking Yuki's blood, he tells Yuki something that leads Ai to ask Aido whether he likes or loves Yori. It is also revealed that Ai considers Zero as her father, although she knows Kaname is also her father too. Zero later clarifies to Aido that he told Yuki that he thinks he's in love again after all this time. A blushing Aido asks for what happens next and Zero reveals that Yuki hugged him tightly and patted his head, the way a mother would her child. Aido reassures Zero that it's still love and wishes him good luck.
While Ai is still a toddler, although a bit older this time around, she appears to be in full swing of rooting for progression in Zero and Yuki's relationship. In an exchange diary between her and Zero, she tells Zero that it's now his chance with Yuki and to do his best. Zero is visibly uncomfortable with this, expressing guilt that he acknowledges he shouldn't feel. His future self narrates that he had no idea of knowing he and Yuki would announce their relationship to everyone, only having to do this because of people who, like Ai and Yori, wanted to know about the progression of their relationship. At this point in time, Yori and Aido are in a relationship and are looking to get married one day. As Yori is a human, it complicates things for Aido, who feels it inappropriate to marry before his boss. She seems frustrated by the fact that Zero and Yuki are in a lull of sorts, but quickly snaps out of it, explaining her worry about becoming old if she keeps waiting because of Aido's reluctance due to Zero and Yuki's lack of progression. Before parting ways, she smiles at Zero and tells him that she's rooting for him and Yuki. Zero smiles warmly and thanks her. However, Yori wonders as Zero walks away with a cluster of girls following behind if it'd be okay for her to root for Yuki.
Yuki, who is using formalities with Zero at this point, asks for the exchange diary as he is playing with Ai. Zero holds Ai back as Yuki reads the diary in horror, as the contents of the diary include intimate details of Yuki's private life. She assures Ai, however, that she hasn't done anything wrong, instead praising her for improving her writing. Before Zero can leave to take a nap, Yuki ushers him into another room. The two kneel opposite each other on the couch and talk. Yuki lectures Zero for not telling her about the contents of Ai's diary, even though he knew. Zero responds with his intention to tell Ai to write about herself, and points out that she was not subtle in checking the diary herself. Yuki, appearing a bit flustered, says that she would've seen his diary too, but Zero doesn't mind this. While fidgeting, Yuki says she'd be troubled if she saw his diary. Zero sighs and asks why, but Yuki is reluctant to elaborate. He threatens to spread a rumour about her underwear being inside out at a soiree if she doesn't tell him, prompting her to burst out that he'd likely have written about Yuki being cute and that he likes her, scolding him for making her say it. Zero seems to confirm this with a small 'how did you know?'
The previously light tone turns serious and Yuki's expression becomes distressed. She expresses happiness at Zero visiting her, but dismay at not being able to answer his feelings, thinking herself the worst for it. Zero takes her hand and reassures her, apologising to her as he does so. He shows understanding that her heart has yet to move on, and makes his intentions of not rushing her clear. He also assures her that his feelings for her will not change, and when she asks him to leave if he doesn't need her anymore he pulls her hand closer to his face and tells her it's out of the question, as he only desires her blood. He then reveals that Yuki has only ever desired his blood, too - but until the day she can acknowledge the implications of that at his fullest, he can accept it as her finding his blood particularly pleasing. Yuki, in turn, reveals to Zero that she did in fact read part of his diary. She quotes his writing to Ai about her birth causing her mother to smile a lot, and expresses happiness with a smile that Zero wrote that. Zero tells her that it's great Ai was born and Yuki agrees. She thanks him for being with her and feeds from his neck.
The narration of his future self returns, revealing that leaving things to time was the intention, but not everyone was happy with Zero and Yuki living in peace. Zero is shown being targeted by a cloaked man, who tells him to stay away from Yuki. He tells Zero that he is a follower of Yuki, and Zero is unsuited for a Pureblood as a hunter. He tells him to stop defiling Yuki with his 'dirty hands and blood', and upon Zero's refusal the two fight. Zero comments via narration that it is only Yuki and Ai who can take him from Yuki's side. After defeating the cloaked assassin, Zero finds out that Yuki has been following him with her familiar. Upset by the attack, which is apparently not the first one, Yuki angrily states that Zero is not dirty, and that it's not only just him (presumably "defiling" the other or being "unsuited" for the other, given the context of future chapters). When Zero arrives at her home, she tells him to leave with an excuse that she doesn't want to see his face for a while. Zero sees through this but lets Yuki leave regardless after she admits she can only get her followers to understand her anger by telling them.
Yuki confronts her followers with anger over what they did to Zero, a swarm of butterflies following as she walks. One woman tries to reason that few are happy with her relationship with Zero, pleading that she choose a Pureblood instead. Yuki asks if that's what she must do in order for them to treat her respectfully, and the woman admits that they ultimately cannot oppose her because of her power as a Pureblood by nature. A servant girl spills the true feelings of the others in a sinister fashion, much to the annoyance of the other vampires. She tells Yuki that there's worry of Zero and Yuki having a child together, which would cause a lot of annoyances among the vampires. Therefore, those in opposition are doing their best to come between them. Yuki confirms that they are doing just that and summons Artemis. She threatens the vampires, telling them that they will only needlessly die if they carry on coming between her and Zero and attacking the latter. The vampires don't say anything, but appear solemn.
On Zero's side, his coworkers plead with him to break up with Yuki. Zero rejects their plea, stating he is not pushing Yuki away ever again. He expresses understanding at their feelings, as he knows he has reasons to absolutely hate vampires and Purebloods with the core of his being, but he also acknowledges darkly that they don't understand how it feels to experience the 'deprivation of loss'. Coming to his senses, he holds his head and admits that he's not strong enough to go through it again. Telling his coworkers that he doesn't care about his ranking in work, as long as he keeps his gun, Zero goes to leave. His coworkers, however, clarify that the matter of his job is different altogether to that of his relationship. It's the reaction from vampires and hunters who disapprove that is their true concern.
Following these events and a further attack that prompts Aido and Yori to become engaged, Zero and Yuuki decide to meet on a specific bench at Cross Academy. It is this very bench that becomes a prominent part of their relationship for decades to come. 
When Ai is a young child, she begins to question why Yuki and Zero still aren't moving forward. This is symbolised by a box that she metaphorically threw away the lid of, something that she deeply regretted as a child but not in the present. During a conversation with her mother, Ai asks if she loves Kaname. Yuki confirms this, but when Ai tries to ask about Zero she is cut short. Zero escorts Ai and Yuki to Ai's first soiree, wishing her luck before they go. After a disastrous evening, Ai and Yuki leave early. Zero comes to pick them up, and is embraced by a tearful Ai. He carries her to the car, and she expresses happiness when only Zero is the one touching her. Before leaving after dropping them home, Zero teases Yuki about showing him her dress next time around. After he's gone, Ai comments about Zero not visiting as often any longer, wondering if it is because he and Yuki are both busy. Yuki clarifies that, although that is true, they decided for him to not visit so often together anyway (presumably because they meet at the bench instead).
Ai wonders as she looks at her mother if it's just that she doesn't need Zero anymore. Yuki notices and asks Ai what's wrong. After a moment of great hesitation, Ai suddenly bursts out that perhaps Zero is angry that Yuki loves Kaname still. The metaphorical box opens, and Yuki's face darkens. She explains to Ai that, after Kaname went into the coffin, she stood there without eating or sleeping. In her head she'd planned to kill all vampires in existence, so that Kaname would not have to sleep any longer in the coffin. It was only Zero, at the time, who could stop her. Zero and Ai both, however, came to rescue her from that darkness.
Whilst in the bath, Yuki opens up to Ai about the story of her, Kaname and Zero. She recollects a time when she was still pregnant, stood at the furnace with Zero. Zero asks her if she's had thoughts of bringing Kaname back and allowing vampires to live without weapons to control them, or if she'd go about slaughtering them all and bring back Kaname that way, either way having him fulfil his duty with his 'flesh and blood'. Zero states that he wouldn't want her to leave the baby behind in that sort of world, and Yuki agrees with a sad smile. Yuki finishes her story, acknowledging that it's censored due to Ai's age. She tells her that the reason why things have to stay the way they are now is to protect 'someone', a person she can lean on and carries the same feelings as her. Ai knows this person to be Zero.
Realising she is developing a crush of her own on Zero, Ai asks Yuki if she is lonely. Yuki brushes off her question with a laugh, but it only serves to upset Ai further and strengthen her resolve. Upon confessing to Zero, he lightly lets her down, stating that the only wife he'd take is Yuki. Accepting this with a sad smile, Ai and Zero dance and she vows to put aside her feelings. She later reflects on doing this as the best, most important decision in her life, as it allowed her to understand the feelings of the trio - making reference to the metaphorical furnace and the seed of desire. After this event, she locks Yuki and Zero in what appears to be a storage closet, yelling for them to hurry up and marry. Yuki and Zero exchange gazes after briefly wondering what to do to get out, and Ai narrates that there was no way she could have known it'd take a few decades more. 
As an adolescent, Ai is housebound due to her vampire urges beginning to take form inside her. Yuki reveals that she knew about Ai's feelings for Zero were beyond her not wanting him to despise her. She saw her return crying after her confession and knew that her feelings were true, and that she put an end to it herself. She also knows that, in this state, she wishes Zero were here too.
After overcoming her unstable thirst, Yuki is free to meet up with Zero again. The two offer each other blood at the same time, causing them both to smile. Zero remarks about feeding being more practical than sexual at this point. As Yuki talks about Ai, his inner monologue comments that, although they are meeting in a safe place, their relationship is stagnant. He comforts Yuki as she cries, knowing she is crying for Kaname, but that this weakness shown is only shown to him. Yuki, at one point, comments about nice couples who can work through any hardship together. Zero, who is lying with his head on her lap as he watches her, knows she is sorting things out in her head, but that would still not change their relationship.
Following one particular occasion where an argument between Yori and Aido is resolved in front of the pair, Zero asks Yuki as they watch the couple leave with their baby if they, too, will ever be like that. Yuki looks at him, and he asks if they can just try by holding hands. She reaches out her hand and holds his, something Zero takes note of later on. They both wonder why Kaname enters their thoughts when holding hands, but Zero tells Yuki that this doesn't matter and tightens his grip on her hand. With a squeeze of her hand, Zero tells Yuki he will love her even where Kaname still remains. When she starts to tell him how unfair the situation is, with her not answering or allowing him to leave her, he cuts her short by kissing her hand. He tells her that her gentle hand saved him many times, that her smile makes him happy, and that he is fine with her. Though she doesn't respond, Zero remains hopeful, but time still flies by with the relationship remaining stagnant. 
During a conversation with Yuki one day, Yori embraces her after she agrees to turn her if needs be. At some point in the conversation they talked about Zero, and this is brought up again by Yori. She acknowledges that it's not easy for Yuki to answer Yori when thinking of Zero's welfare, but with a sigh she admits she wonders why they can't move forward even though they have mutual feelings for one another, going on to ask if something happened. Yuki answers with a smile, and Yori asks if there are things she's better off not knowing. Before finishing her conversation, Yori cups Yuki's face in her hands and tells her that hurting herself will undoubtedly hurt her precious person too. 
Years later, when reflecting on her mother's memory of an encounter with Rido and the terrible seed of desire, Yuki asks Zero if he'd still drink her blood should she have turned out like Kaname or Rido. Zero, visibly in comical disgust, is asked by Yuki to not imagine that scenario. She talks about how frightening it is to have a greed that either puts you or the world in turmoil, but admits her greatest fear is the seed inside her own self, and the ability to use it the way Kaname and Rido had. Zero remarks that she sounds like Kaname, and lightheartedly Yuki takes it to mean she's getting old. When Zero doesn't respond, she becomes gloomy and bursts out that she wants to be smart like Kaname if she's to be like him, for Ai is too smart for her.
Annoyed, a teenage Ai appears from the bushes and lectures the pair for their conversation pattern. She declares angrily that she will sulk in bed until a sister is born for her, even if she dehydrates like a mummy. After Ai leaves, Yuki apologises to Zero for her behaviour, but Zero shrugs it off. Yuki then apologises to Zero for her own behaviour, admitting that her heart is still aching. Zero holds Yuki close and admits he feels the ache to when at the furnace. He comments that Kaname left a huge burden for Yuki, the woman he loved.
Meanwhile, Ruka and Kain are on the rooftop of one of the buildings. Ruka is using binoculars to spy on Yuki and Zero, acting as a cheerleader on the side by rearranging Yuki's schedule so she can spend time with Zero. Ai, who left to find intruders, is caught in a sticky trap behind her. Ruka apologises for setting the trap, explaining that Zero and Yuki need the time alone together. When Ruka asks if she's worried because she wants their happiness, Ai denies this, claiming that she only wants a sister to act as a blood bank, adding that she doesn't want her to look like Zero. Ruka points out that it's easier to find someone to love, with Ai revealing something reminiscent of the terrible seed - that Zero, who belongs to Yuki, was the one who she wanted to 'trap, dress up and keep' as her very own prince. Ruka embraces Ai, understanding that she put Zero's happiness before these feelings. When she goes back to spying, Ai asks to join, but Ruka refuses to let her.
Once Ruka stops spying, Zero pulls Yuki down so her head rests on his lap. He tells her to get some sleep, because she hasn't been able to lately, remarking that even a tough monster needs to rest. Yuki, smiling, tells him not to call her a monster. Meanwhile, Ai asks Ruka why she is so invested in Yuki and Zero's relationship. Ruka reveals that her investment lies in the fact that Kaname's last wish was for the two to be together, that he wished for her happiness. At the bench, Zero tells Yuki that although he didn't answer immediately, he would love her even if she was wrinkled and lost her youth. He adds that she hasn't aged at all, she's still just as cute. Yuki reaches up and touches Zero's face, surprising him, and replies that he's still just as handsome. She tells him that his words woke her up because she was so happy to hear them. Zero then stops her from talking about work, instead asking about the seed of desire. She pokes his nose after telling him it's a desire born out of distorted love, teasing that the rest is a secret. At this point, Ai lets go of her feelings for Zero once and for all. 
Decades later, Zero visits a frail Yori at hospital on her birthday. She is visibly exasperated at the nature of Zero and Yuki's relationship. Zero, knowing it's a tired excuse, tells her they're busy and have their positions to consider. Yori counters that the two still feed from one another, and asks what he will do if a man takes Yuki from him. Zero is assured that it wont happen, because she has been bound to Kaname since her birth. Yori supposes that it's not a good thing to have all the time in the world, because decisions don't have to hurry and be made. Despite this, she is looking forward to receiving a wedding invitation, no matter how long it takes. She expresses the desire for Zero to live happily with Yuki, and assures him that things won't stay as they are at that point forever, adding that he hasn't changed and is well suited for Yuki.
Shortly after this, Yori passes away. At her funeral, Yori's grandchildren ask Yuki to be her friend, as it was a wish of their grandmother's. Yuki agrees, asking if they'd be friends with Zero too. Zero is revealed to calm Yuki at funerals such as these by allowing her to drink his blood. When walking together, with Yuki grasping Zero's sleeve, Zero tells her to stop crying already, adding his disbelief that she's a mother to a child. Yuki argues that Ai is grown up, and Zero agrees, stating she is more grown up and smarter than Yuki is, prompting her to tell him to shut up.
After a brief pause, he reflects on the last conversation he had with Yori, comparing himself to her. When Yuki asks why, he says her stupidity relieved them both, causing Yuki to question why they both are so mean, and Zero that she can be difficult sometimes, which Yuki apologises for. When Zero starts explaining his difference from Yori, they are interrupted by Seiren. Before Yuki can leave, Zero grasps her hand. He confesses that, unlike Yori, he has a regret. He regrets not doing anything to keep her at his side upon finding out she was a Pureblood. He wonders what would have happened if he grabbed her by the arm and told her not to go. He regrets that he did not honour that moment he had, when he wanted her with all of his heart but turned his back on her, even though all he thought of was losing her.
Acknowledging that Yuki is waiting to revive Kaname someday, Zero urges her to honour her time and do what she wants to do with her own life. He reveals that, though she loves Ai and Kaname, she loves Zero too, and asks her if that's enough for her. She smiles in response, and Zero's inner monologue reflects on how she brought warmth to him when they met, with him then verbally expressing his happiness for meeting her in this lifetime.Some time after, when Yuki is napping on Zero's lap as he reads, she awakens from a dream of Kaname breathing in fresh air and holding a baby, and hopes that this dream will come true one day.
A year after Yori's death, on a certain holiday, Yuki stands before Zero. She acknowledges that inevitably the day will come for her to revive Kaname, an incessant thought that won't go away. She confesses that, for a time she thought she'd face this future alone, but Ai and Zero were there for her. Because of Zero being there at her side, she is able to smile even in that moment, and expresses the desire for Zero to smile too. Addressing him by his full name, Yuki introduces herself as a Pureblood vampire and asks for him to start over with her and date her. Zero, amused by her antics, takes her hand and pulls her into an embrace shortly after. Yuki once again thanks Zero for being by her side, and also for liking her as she is. Zero states that it is he who should be saying this.
Shortly afterwards, the pair are spotted by Rima and Shiki on the way to visit Kaname. Noticing they are holding hands, Rima remarks that having a partner to lock hands with and run through anything with feels nice. Upon arriving to visit Kaname, Yuki and Zero encounter Ichijo, who guards Kaname's coffin. Zero states that their intentions are to publicise their relationship and check for any objections. Ichijo awkwardly says he has no objections, and quickly backtracks when he wonders what would happen if he did, calling it a joke as the two sigh in relief. As Ichijo watches the two go inside, he remembers Aido's lament over the couple not moving forward, believing that both felt unworthy of the other. He smiles, thinking Aido will now be relieved.
Zero and Yuki stand beneath Kaname's coffin and tell him of their relationship, with Yuki gripping the back of Zero's coat for comfort. When the couple are later out together, they are stopped by an elderly woman who was saved by Zero as a small child. Zero denies knowing anything about this event and watches the woman off, acknowledging to Yuki that he did in fact save that woman as a girl. Yuki, in response, plucks a hair from his head. She admits with a smile that it's good the girl got to live happily, even though it feels lonely to have been left behind.
The couple enter Zero's home, a place Yuki has not been to before. He pours tea for them, and the two sit at the table together. She apologises for the unhappiness shown when they announced themselves to people, and Zero questions why she is apologising. When he moves on to ask about dating from step one, Yuki jumps up, realising that Ai hasn't been told. Zero reminds her that Ai is dormant, and Yuki reveals that she will be for another 30 months. The reason behind this, according to Zero, is that Ai doesn't want her soul to grow old. Yuki seems visibly troubled by this, and Zero assures her with a loving smile that he will grow old with her. Yuki's expression prompts Zero to ask what's up, but Yuki shrugs it off.
Zero admits he doesn't understand what Yuki means by dating from step one. Innocently, Yuki asks if it's about getting to know each other. She elaborates by saying it meant things like holding hands, going to school and eating lunch together - but each time these innocent suggestions are countered by Zero, who points out that those things have already been done plenty of times. Yuki holds herself, realising that neither are innocent any longer. Zero steers the conversation into getting to know Yuki, asking her why she still wears the bracelet when it no longer has any power. Yuki reveals that her bracelet is kept on as a reminder of her promise not to kill Zero, to not let his future be blackened by his past. She hoped that her kind partner would smile peacefully someday. Zero admits that he somehow knew she felt that way, and the pair's conversation comes to a close after a comment about the time that has passed. After an intense stare, Yuki reaches for Zero. He grabs her hand and, while on top of her, tells her he wants to drink her blood to his heart's content. Yuki urges him to do so, even if it's to the last drop. 
Some time after this occasion, Kaien becomes sick. It's clear that, although he has had an incredibly long life span, his life is coming to an end. Yuki and Zero come to visit, and Kaien overdramatises his condition to Yuki, who weeps and makes promises to do whatever Kaien wants. Zero, seemingly unaffected, assures Yuki that Kaien will not die yet and the two go to leave. Zero promises Kaien he will return if he stays alive. Shortly after leaving the room, Yuki returns to promise that she will also visit again. As she does so, some coworkers of Zero's pass by. They ask Yuki not to dump Zero, because he becomes gloomy and scary when he's shocked. Zero turns up as they say this, and Yuki questions what he was shocked about. Kaien watches fondly as Zero and Yuki bicker, then closes his eyes and smiles. On their way out, Zero reassures a frustrated Yuki about Kaien and his idiocy in this situation. Kaien asks in a monologue to Juri if he did a good job, acknowledging that there were some results he was not happy with, but he ultimately was able to sow a few good seeds. 
Aido, who is working hard on finding the cure still, stops Zero from leaving one day after he turns up bloodied with a fugitive that is no longer needed by Aido for experimentation. He seems upset when Zero mentions the violence that comes with capturing live vampires, and after prompting from Zero, he confesses his wish for Zero to cherish his own life. Zero seems visibly discomforted by this, which causes Aido to become flustered and explain that people like Yuki would be heartbroken if he died, which by extension would devastate Yori. He points out that Zero, no matter what, will die sooner than Yuki, and says he should be spending lots of time with her. Zero, after a quiet moment, says that he never imagined Aido would teach him something that was right under his nose, but yet he couldn't see it. He thanks him with a sincere smile, and it is revealed that Yuki was watching through her familiar the whole time.
Yuki, who is out with Rima and Ruka, snaps out of her watch over Zero and Rima gets straight to the point, asking if there is development in her private life. Yuki avoids the question by mentioning the disappearance of Kaien, who has gone travelling for something, and Ai going back to sleep. Rima takes a more direct approach and asks about Zero, who was supposed to start from step one with Yuki. Yuki reveals that they spend more time at each other's homes and Zero doesn't hold alcohol as well as Yuki does. Rima grows impatient, and is scolded by Ruka, who asks if Yuki intends to officially bond with Zero someday, and Yuki says that although they may do it's not likely to make much of a difference to their relationship. Ruka shows understanding of this, comparing the situation to that of hers with Kain. Yuki confesses that Zero is family and her irreplaceable partner, and nothing can change that.
The girls part ways and Yuki starts heading home, but an explosion nearby stops her in her tracks. She arrives to see Ruka and Kain and is visibly distressed at the situation. It is revealed that a new terrorist threat has been made by someone calling himself the "King of the Vampires", with the intention of causing hostility towards vampires. After talking about this incident briefly with Zero while in bed, Zero bids her goodnight and goes to leave. However, Yuki grasps his sleeve and tells him sheepishly that they should sleep together once in a while. As the two lay in bed holding hands, Zero starts to speak about the fact that he isn't reluctant, but trails off. Yuki looks over to see Zero asleep and places her hand on his cheek. She then climbs over him, bites her wrist and draws blood, feeding it to him through a kiss. He takes her arm, and the kiss breaks off.
As she cups his cheek, Zero asks her what's wrong. She briefly brings herself closer to him, but then shuffles to his side and brings up the bombing incident again. She wonders if Zero still believes vampires and humans can only be enemies, and worries of the consequences should any human find out about Purebloods. Noticing her solemn expression, Zero ruffles her hair. She grabs his wrists and pulls them over his head, scolding him gently with a smile before flopping down next to him. Though her approach becomes more optimistic, Zero tells her not to be too reckless. Yuki replies that the same goes for him, and he agrees as he goes back to sleep. Yuki watches him sleep, but is still visibly troubled.
At work, Zero's coworkers joke about the fact that Yuki's familiar is following him about everywhere. On a job, he is faced with a dangerous vampire who has an explosive inside his body. He urges everyone to get out and protects them as the blast goes off, with Yuki as a witness via familiar to the whole thing. Ruka and Kain later marry in a ceremony that has them vow to be together until they turn to dust. Yuki watches with a sad smile, and later remarks that the ceremony was nice when in her room with Zero. He, however, is visibly unhappy and reminds Yuki that they said they'd start over from the beginning. When Yuki acts oblivious, Zero becomes visibly irritated, pointing out the expression she made at the wedding. Finally, he pins her to the bed and yells at her to say what's on her mind, assuring her that it's fine to say it.
Yuki, visibly upset, cups Zero's face in her hands and asks Zero to live for as long as he can, revealing her deep fear that he could die soon and that she thinks about it whenever something happens or someone dies, but she feels she can't say it because it's a curse to him. Zero tells her that she is the one suffering under her own curse, and to give him her cursed blood that rejects death, cursed blood that will delay his death for eternity. He proceeds to bite all over Yuki's body and draw blood. Yuki tells him that, if it's possible to do that, she wants to do it most of all. Zero holds Yuki in his arms afterwards and tells her that he will declare idiotically that he was happy to spend his life with her. She tells him again to take her blood, the blood of a growling beast. Zero, panting, claims he wont be able to stop, and questions why her blood is so irresistible as he tightly embraces her.
A few years after Ai's slumber, Ren is born.
Having saved a stranger's child, Zero returns home to Yuki fatally injured and clinging to life. They embrace and she scolds him for protecting a child he didn't even know. He kisses her tears and then her lips, and she agrees to grant his final wish and devour him. After he disappears, Yuki collapses to her knees in floods of tears, declaring that she, like Zero, was happy. 
Shortly after this, she visits the Kiryu grave site with Ai and Ren. Whilst holding a fragment of the Bloody Rose, Yuki reveals that although she fought any times with Zero, he made her very happy. She finally leaves the fragment at the grave site and goes to sacrifice her life to revive Kaname.
- Zeki is the western naming convention for this ship. The name combines the Zero and Yuki to create the name Zeki.
- The most commonly written Japanese name for the ship is 零優 - again combining the names of Zero and Yuki.
- Interestingly, Zeki is a Turkish name that translates to 'intelligent' or 'clever'. It is also considered a shortened form of the Hebrew name Ezekiel, which translates to 'God will strengthen'.
- Yuki & Zero were voted most popular couple in the January 2008 LaLa poll with 1700 votes.