Boy Psycho summary: Thanks to his mother's remarriage, Amou Reishin becomes part of a family that leads one of Japan's leading business conglomerates. Unbeknownst to him, the company's underworld business is that of assassination. His stepbrother Garaku is a psychopath who enjoys particularly sadistic ways of killing. Now Reishin and his sister Sarasa are Garaku's new playthings.