Scapegoat Family

Junpei has decided to marry Minami Akutsu—a beautiful woman who lives in a luxurious mansion—and is set to become a son-in-law to the Akutsu family. There are strange household rules, a creepy basement, and a series of disappearances happening behind the scenes. This happy "family" is harboring a terrifying madness.

(Source: Nihonbungeisha, translated)