Shin Megami Tensei: Devil Children: Kuro no Sho is a role-playing video game for the Game Boy Color released by Atlus. Players control Setsuna, a young hero on a quest to rescue her kidnapped brother from a realm inhabited by demons. Accompanied by the demon Cerberus, Cool, Setsuna navigates a richly crafted world, engages in turn-based battles, and captures various demons to aid her journey.
Black Book follows Setsuna, whose little brother has been kidnapped by an army of Jack Frosts and taken to the demon world, and who is accompanied by the Cerberus Cool.