Yuki Cross or Yuki Kuran is the adoptive daughter of the headmaster of Cross Academy. Yuki is a first year student at Cross Academy and is a member of the school's disciplinary committee, which is a Guardian for Cross Academy. In her capacity as a Guardian, she is responsible for the nightly duties of monitoring and protecting the Day Class. Yuki carries the anti-vampire weapon, the Artemis Rod. Also she is 15 (16, during the one year time skip).
Yuki is generally a cheerful and comedic girl. She exhibits a strong attachment to her close friends. Her indecisive nature and reticence can be attributed to her insecurity regarding her missing history. She has a fear of vampires which means she rarely leaves the Cross Academy grounds on her own. She is protective over Zero and fears the fact that he might become a level E. She is a bit shy of realizing the fact that she has been in love with her own brother for all those times she was a little, as a human and when was reawakened, having grown as a human for 10 yrs. She also acknowledges the fact that there's a link on a part of her heart she cannot cut that is attached to Zero, but her thirst for his blood did not keep her beastly need for Kaname’s blood and the want to be with him. Her personality as a pureblood lessen her indecisiveness, her determination to do things she likes often put her and Kaname in disagreement where she normally win in the end. Yuuki’s pureblood nature is not far from being a jolly and comedic young human girl she was, but when a situation asks, she can put in an authoritative face as is expected for a pureblood princess just like her brother/fiancé Kaname.
Yuki was approximately 5 years old when Rido Kuran attacked the Kuran family seeking to take Yuki. To protect her daughter, Juri sacrificed herself to seal Yuki's vampire side and erased her daughter's memory. Yuki's first memory is that of Kaname saving her from a vampire. Yuki grew up harboring deep feelings for him and they had a mutual relationship though Yuuki is shy in admitting that it is love as she sees that Kaname is different from her, that a vampire and human can’t be for each other.
Yuki as a child had troubled nightmares nightly until Zero Kiryu joined their household and Yuki formed a strong attachment to the boy. Yuki's relationship with Kaname became distant after she witnessed his vampire nature as he fed on a vampire classmate and as a human, Yuki believed she had no chance with Kaname and began to distance herself from him, but her admiration and longing for him remained.
She is in love with Kaname but also cares deeply for Zero.
Yuki's best friend is Sayori Wakaba whom Yuki calls "Yori-chan". Sayori is her roommate, too.