Yuuki is a student at Cross Academy and serves on its disciplinary committee (also known as the public morals committee in Japanese). She was adopted by the headmaster, who took her in after she was attacked by a vampire ten years ago. Despite losing all memory of her past life, Yuuki has developed strong feelings for Kaname, one of her classmates at Cross Academy. Although she witnessed his vampiric nature when he bit Ruka, she remains deeply in love with him. Recently, Yuuki has allowed Zero, a childhood friend, to drink her blood in an attempt to save him from madness. She is known for being cheerful and easygoing, and thanks to her work as a Guardian, she is able to remain calm under pressure. There have been hints that Yuuki may be special due to the fact that vampires are particularly attracted to her blood. Her weapon of choice is an extensible staff called the Artemis Rod, which was given to her by Headmaster Cross.
164 cm (vampire form)
Eventually, it is revealed that Yuuki was born a pureblood vampire, a member of the Kuran Clan. Her mother had sacrificed herself to seal Yuuki's vampire side, as well as her memories. Yuuki's existence was hidden from the other vampires. She was kept in a basement in the Kuran Mansion without any windows in order to protect her from both her parent's older brother, Kuran Rido. It was when he attacked the Kuran family, seeking to take Yuuki, when her memories and her Vampire side were sealed.
Eventually, it is revealed that Yuuki was born a pureblood vampire, a member of the Kuran Clan. Her mother had sacrificed herself to seal Yuukis vampi
This also makes her Kaname's sister, and his intended fiancee, meaning Yuuki was born to be his wife.