Vampire Knight

Vampire Knight (ヴァンパイア騎士 ,Vanpaia Naito?) is a shōjo manga and anime series written by Matsuri Hino. The series premiered in the January 2005 issue of LaLa magazine and is still on-going.

Plot
Years ago, Yuki Cross, a high school student at the age of 15 in the Cross Academy of the Day Class, was attacked by a vampire and saved by Kaname Kuran, another vampire. She has no memories of her past before this day. Thus, she was adopted by Headmaster Kaien Cross and later on became a prefect for his school which has one main purpose: that vampires would coexist peacefully with humans. Her job as a prefect includes guarding the tranisition between the Night Class, a class of strikingly beautiful people, actually vampires, and the Day Class. Zero Kiryu, fellow prefect, who also was adopted by Cross and therefore becoming her "brother" has a tragic past: his parents were killed by a pureblood vampire and now he's determined to kill them all. Upon discovering that Zero was bitten by a vampire 4 years ago, Yuki tries to save him from falling to Level-E vampire by offering her blood to him and therefore deepening their bond. Yuki's quest is now to discover her past and what really happened that night that Kaname, leader of the Night Class saved her and what he's really hiding from her.

Yuki Cross
A prefect at the school whose jobs include the separation of the Night Class, a class consisting of vampires and the Day Class. She was rescued from a vampire when she was five, by Kaname Kuran, the leader of the Night Class (and a pureblood vampire). She doesn't have any memories before this day and embarks on a journey to find why every time she tries to think about her past she starrts hallculating and has a headache. She later discovers that she is actually a pureblood vampire, the sister of Kaname Kuran, and had the vampire part of her put to sleep on the day her parents were murdered to protect her against their murderer, Rido Kuran, her powerful, although crazy uncle and another pureblood.