Takuma Sakamoto (voiced by Mizuna Masaaki) is called Diablo in the game. He has superb operating skills and terrible strength. He is called "Demon King" by other players. In an accident, Takuma actually came to the world in the game, where he met two women, Sera (voiced by Serizawa Yu) and Rem (voiced by Kazumi Waki). The two of them released the slave spell of taming summoned beasts to Takuma at the same time, but they did not expect to be backfired. The two who wanted to enslave Takuma became Takuma's slaves instead. This embarrassing situation made Takuma feel very embarrassed, because although Takuma has powerful spells, he is not good at dealing with girls. The lively and cheerful unsuspecting Selvi (voiced by Okubo Rumi) and the gentle-looking but dark-hearted Alicia (voiced by Hara Yumi) appeared next to Takuma one after another. These lovely girls.