傷物語 -こよみヴァンプ-

During spring break, Koyomi Araragi encounters a blood-chillingly beautiful woman—a vampire. On the brink of death after losing her four limbs, she asks Koyomi to save her. After experiencing fear, chaos, and finally conflict, Koyomi gives his own blood in order to save her. But when he awakens, he finds himself re-born as her vampire kin.