Ep. 1: Akihito survives Mirai's sword attack and learns of her clan's tragic fate.

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High school student Akihito Kanbara attempts to prevent freshman Mirai Kuriyama from jumping off a roof, only to be impaled by her carmine sword. Mirai survives and stalks Akihito, who reveals his immortality as a half-youmu to her futile killing attempts. After Spirit World Warrior Shizuku Ninomiya defeats a youmu, Akihito dines with Mirai, discovering she used him for battle practice. He later learns the Kuriyama clan was destroyed due to their blood weapon ability, leaving Mirai as the sole survivor. Despite warnings from friend Mitsuki Nase, Akihito chooses to help Mirai confront a youmu haunting her home, empathizing with her hatred for her cursed powers and the act of killing.