Takuma Sakamoto, a shut-in gamer, is transported to a fantasy world as Diablo, the Demon King, after two girls unwittingly summon him. The ritual backfires and the two girls Rem and Shera become his slaves, while he uses their status to take control and protect them. With MMO-level power and a sharp mind, he faces monsters, intrigue, and a mix of comedy and ecchi moments.

Takuma Sakamoto, a shut-in gamer, is transported to a fantasy world as Diablo, the Demon King, after two girls unwittingly summon him. The ritual backfires and the two girls Rem and Shera become his slaves, while he uses their status to take control and protect them. With MMO-level power and a sharp mind, he faces monsters, intrigue, and a mix of comedy and ecchi moments.