Legends foretell that there is a god known as Mr. Fukushuu enshrined in a small altar in the outskirts of the town. He will grant your wishes in exchange for a friendship with you. However, according to ominous rumors, whoever befriends him will eventually die.
Tadashi Satou suffers from violent bullying at high school everyday. The bullying reaches a critical point when his bullies raped and murdered his one and only living family, his older sister Haruka. In his despair, Tadashi prays to Mr. Fukushuu at his shrine, offering him a friendship and even his life in exchange for revenge. Suddenly, a strange man who identifies as Mr. Fukushuu appears before him, promising to aid with his desire for revenge. Who is this man, and what kind of revenge does he have up his sleeves?
— Description from AniList community (anilist.co).
