(異世界魔王と召喚少女の奴隷魔術, Isekai Maō to Shōkan Shōjo no Dorei Majutsu )
In the realm of Tenkoku, where powerful beings known as Demon Lords held sway, a young man named Takuma Sakamoto found himself transported to a world within a game he had played in his youth. The game, "Cautious Hero: The Hero Is Overpowered but Overly Cautious," had been his guilty pleasure, and now he was living it. how not to summon a demon lord wiki