When a human is bitten by a Pureblood vampire, they will either die from blood loss or poisoning or more likely suffer the slow agony of the awakening to become a vampire. These vampires are easily controlled by their master and are unable to kill their creator. One of the few advantages is that unlike normal vampires, they are not overly sensitive to sunlight.
When Hunters capture level D vampires, they tattoo them with their symbol and perform a "taming" ceremony enabling them to disable a vampire with a linked piece of jewelry. While the hunters have a ward to prevent vampires from entering their buildings, an exception is made for tamed vampires.
Eventually every ex-human vampire falls to level E, and loses his or her humanity and goes mad with bloodlust. These vampires are then put on the list for extermination. However, they can be saved from this fate if the Pureblood that created them gives them their blood.