Vampire Knight 

ヴァンパイア騎士

Cross Academy is attended by two groups of students: the Day Class and the Night Class. At twilight, when the students of the Day Class return to their dorm, they cross paths with the Night Class on their way to school.

Yuki Cross and Zero Kiryu are the Guardians of the school, there to protect the Day Class from the Academy's dark secret: the Night Class is full of vampires. Yuki's earliest memory is of a stormy night in winter, wherein she was attacked by a vampire... And then rescued by another. Now 10 years later, Yuki Cross, the adopted daughter of the headmaster of Cross Academy, has grown up and become a guardian of the vampire race, protecting her savior, Kaname, from discovery as he leads a group of vampires at the elite boarding school. But also at her side is Zero Kiryu, a childhood friend who’s hatred for the creatures that destroyed everything he held dear, is now determined never to trust them. 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? Is Kaname's infatuation with Yuki the beginning of a forbidden romance, or is it something in her forgotten past that draws him to her? In this world of secrets, nothing is as it seems, and the price of misplaced trust may even be worse than death.