The Strength of Pure Soul

Yuki Cross' earliest memory is of being all alone on a snowy night in winter, when she was attacked by an evil "Level E" vampire and saved by a powerful but kind vampire named Kaname Kuran. Ten years later, Yuki is a school guardian, protecting the human "Day Class" students from the vampire "Night Class" students, along with her childhood friend, Zero Kiryu. The story follows Yuki's discovery that Zero has been turned into a vampire and her struggle to keep him sane and prevent him from killing himself as he fears turning into the lowest level of vampire, the monstrous Level E, all the while she deals with her unobtainble love for Kaname, who happens to be the highest pedigree of vampire, a pureblood.

Yuki faces a difficult decision with the arrival of Shizuka Hio. The pureblood vampire, who killed Zero's family and turned Zero, offers Yuki the deal of either killing Kaname Kuran or becoming a vampire in order to save Zero. Yuki decides to give up her humanity to save Zero, but is prevented by Zero who would rather kill Shizuka. Neither occurs when Zero's assumed dead twin shows up. Shizuka, instead, is killed by Kaname Kuran. With the loss of his salvation, Yuki continues to help Zero fight his bloodlust while also seeking to recover the memories she lost as a young child. As the series progresses, Zero's thirst for blood leads to his drinking from Yuki, by her consent, to avoid becoming a level E vampire and losing himself to his monstrous instincts. Kaname is very protective of Yuki, and to stop her from having to do this, he gives Zero his own "pure" blood. Also, since he had consumed the blood of Shizuka Hio, his own helps keep Zero from going insane and from needing to feed from Yuki.

Eventually, it is revealed that Yuki is a pureblood vampire herself; the Pureblood Princess of the Kuran family, who had been transformed into a human before she lost her memories. It is also revealed that Kaname is Yuki's older brother and that they were engaged as children to be married. Despite this, Kaname is not Yuki's true blood brother, but an ancient and powerful ancestor of the royal Kuran family who was resurrected by Rido Kuran. He was raised by Yuki's parents, Juuri and Haruka Kuran, after Rido had kidnapped and sacrificed their first child to bring him back to life. To protect Yuki , her mother sacrificed her life in order to perform a spell that would seal Yuki's memories and allow her to live as a human. After Yuki reawakens to her vampire nature, Rido again tries to kill her and consume her power. As Kaname kills the corrupt vampire senate who they had discovered were working together with their uncle, Yuki fights Rido. During a fierce battle, Zero aids her in killing him, but later on tells her he will have to kill her when he sees her once again, since she is a pureblood. She tells him that she will keep running, so that he will have a reason to live. Although this is where the anime ends, the manga continues the story and is updated monthly in LaLa Magazine.