Isekai Maou to Shoukan Shoujo no Dorei Majutsu

In the game Cross Reverie, nobody can rival the Demon King Diablo. Behind that terrifying character, however, is Takuma Sakamoto, a shut-in who barely knows how to speak to people away from a screen. His life changes when Rem Galleu and Shera Greenwood summon him into a world resembling the game, complete with Diablo's body and powers. The two girls attempt to bind him with enslavement magic, only for his spell-reflection ability to reverse the ritual and place the collars on them instead.

Unable to act naturally around other people, Takuma hides behind Diablo's arrogant persona because it is the only role he can perform with confidence. He travels with Rem and Shera while searching for a way to undo the magic, but soon becomes entangled in the secrets each girl carries and conflicts threatening the people around them. With power few can challenge and social anxiety no spell can cure, Takuma tries to protect his companions without exposing the awkward man behind the Demon King.