Towards the climax of arc one, Yuki is revealed to be a pureblood vampire, and the Kuran princess. Hino Matsuri has described Yuki as a healing and soothing character, who exemplifies her justice side. She is often kept ignorant by other characters who know more about goings-on, which results in her character feeling guilty for being unaware of the suffering of other characters.
She is generally a kind, caring, cheerful, and comedic character, but often portrayed as not being very smart, being a poor student due to the fact that she is a guardian at night and student in the daytime, giving her little time to study and sleep. She has been in love with Kaname Kuran, a pureblood vampire, since he saved her as a young child, but her affection is later divided to include Zero as well. Yuki is close friends with Zero Kiryu, who she becomes determined to help once she discovers he had been turned into a vampire, following which their friendship rapidly evolves. She begins as a human, a Guardian protecting the human students from the vampire students. Yuki is the adopted daughter of the headmaster of Cross Academy, a 16 year old first year student who wields the Artemis staff, an anti-vampire weapon formerly used by her mother. While initially developing the characters, Hino reported that though Kaname was created earlier, at every step in the characters' creations, she found it difficult to maintain a balance between Kaname and Zero as she struggled with fears of the former overshadowing the latter. In spite of the secrets held by the two former humans, Kaname is the character with the most secrets, which appear to be the focus of the beginning of the second arc. Zero Kiryu’s revelation as a vampire drives the first half of the first arc and the second half is driven by Yuki’s revelation to be a vampire. The story is set in a school environment and originally the cast is divided into human and vampire students, but after the main three characters are eventually revealed to be vampires, the story moves away from the school environment in the second arc.
The primary character and heroine of the series is Yuki Cross, a naive but energetic human, who is the introductory narrator, she is supported by childhood friend and vampire hunter Zero Kiryu and her crush Kaname Kuran. In spite of being set in future earth, it features a mixture of contemporary and old fashioned technology. Their opponents, the vampire hunters were borne of a necessity for humans to defend themselves against the vampires who were turning their kind into the slave army. The series takes place in an alternative future of earth where global warming occurred ten thousand years ago giving rise to immortal vampires and dramatically reducing the number of humans.
And the price of misplaced trust may even be worse than death.The Vampire Knight manga series and its anime adaption features a relatively small cast of characters created by Matsuri Hino. This coexisting arrangement seems all well and good, but have the vampires truly renounced their murderous ways, or is there a darker truth behind their actions? Because in this world of secrets, nothing is as it seems. At her side is Zero Kiryu, a childhood friend who's hatred for the creatures that destroyed everything he held dear leaves him determined never to trust them. Now ten years later, Yuki Cross, the adopted daughter of the headmaster of Cross Academy, Kaien Cross, has grown up and become a guardian of the vampire race, protecting her childhood crush, Kaname, from discovery as he leads a group of vampires at the elite boarding school.
Yuki's earliest memory is of a stormy night in winter, where she was attacked by a rogue vampire and rescued by Kaname Kuran, a Pureblood vampire.