One day, Yamato Onitsuka is an office worker who accidentally kills someone.The sound effect that rang in your head when you took someone's life.And an announcement informing him of his own enhancement and acquisition of spells. --If a ``murderer'' doesn't kill someone within a week, he will die. Onitsuka Yamato, who became a ``murderer,'' a being whose level increases when he kills someone, has decided to survive even if it means killing someone...