|Princess of Darkness|
|Airdate||June 9, 2008|
|Manga Chapters||15 & 16|
|Previous Episode||Crimson Eyes|
|Next Episode||Compensation of Desire|
|Opening||Futatsu no Kodou to Akai Tsumi|
Princess of Darkness (闇の姫 Yami no Hime) is the tenth episode of the Vampire Knight Series.
Zero remembers telling Ichiru, his twin, to flee after Shizuka’s attack. Presently, he and Yuki are on duty for the Night Class, but the evening is quiet due to upcoming exams. Maria reaches out to Yuki’s face, but Zero pulls Yuki back. Maria then smiles. Alone together, Zero again tells Yuki to avoid Maria.
Later that night, Zero tutors Yuki and says his old neck bite from the vampire that attacked his family aches. Yuki asks what’s worrying Zero and goes to make coffee. Zero comes up behind her and twines their hands; she wonders if Zero wants to drink her blood again. He says Yuki may be why he’s still alive. Then, he leaves.
Meanwhile, Maria and Kaname converse. He knows she’s not Maria and accuses her of toying with everyone. She retorts that he shouldn’t talk morals because they are alike. Kaname plays with a chess Queen and knocks it over; the piece may represent "Maria" in his little game.
Yuki realizes that Maria is the reason why Zero has been acting all strange recently and runs after him. Zero faces down Maria but can’t kill her. She says he can’t kill his master, who made him a vampire. She tries to kiss him, but he jerks back. She and Zero fight. Alarmed, Yuki calls his name, but Kaname puts her asleep. He erases Yuki's memory of that night, saying that he cannot lose Yuki but that Zero can die if he’s that weak. Zero faints from an injury, and Maria tells her bodyguard to carry him away.
The next day, Yuki spaces out during exams as she looks at Zero’s empty seat; Yagari also notes Zero's absense, but keeps quiet. Afterwards, she meets Kaname, and they talk about the ball and dancing. Departing, Takuma notes that Yuki has utterly forgotten last night. Kaname says she’s happier that way. Yagari is with Headmaster Cross, thinking how odd Kaname’s kindness to Yuki is. Kain Cross says Kaname told him to admit Maria and that vampires handle their own affairs. Yagari asks if Zero is a vampire but Kain plays stupid.
Meeting at twilight, Maria uses a scratch from her cat familiar to unlock Yuki’s memories of last night and offers her a deal. She'll tell how to save Zero from becoming a level E if Yuki will do something for her; she has two options.
Meanwhile, Zero dreams of Shizuka and Ichiru. Upon first seeing her, Ichiru finds her beautiful but Zero says she’s a vampire. Ichiru says that Zero's amazing and makes up for Ichiru's mediocrity. That night, Ichiru asks if the vampire they saw earlier will be killed and if kindly Zero will be able to hunt vampires. Zero says Master will teach him to. Then, Shizuka attacks the Kiryu's, out of revenge for killing her lover. Zero sees Ichiru standing next to Shizuka, smiling. He wakes up. Seeing Maria's bodyguard, he coldly greets him. The bodyguard removes his mask to reveal himself to be Ichiru
Compensation of Desire