Vampire School

"Ethan is the only man at a prestigious girls' school, working as the lowest-ranking janitor. After an accident, the entire school becomes mysteriously isolated from the outside world. Ethan discovers that everyone in the school—except him—are vampires. As the only human, all the others depend on his blood to survive, and only Ethan can walk freely during daylight, uncovering the secrets hidden within the secluded school."