Instead of a dungeon that feeds on people's despair, let's build a city where people and monsters can laugh together. Prokel, an eccentric Demon Lord who thought this way, used his power of [Creation] and unknowingly became one of the most feared among Demon Lords, a member of the [Strongest Three]. Due to the jealousy of other Demon Lords, he is transferred to an unknown land. To return to his city, Avalon, and reunite with his beloved monsters, he begins to move together with the [Infinitely Evolving Slime] that was also transferred. He doesn't realize yet that even in the land he was sent to, he will create a new city with new companions and his beloved monsters from afar.