Instead of a dungeon that feeds on human despair, Prokel, an unconventional Demon Lord, decides to create a city where humans and monsters can laugh together. Using his power of creation, he eventually becomes one of the most feared and strongest Demon Lords. However, due to the jealousy of other Demon Lords, he is transferred to an unknown land. Determined to return to his city of Avalon and reunite with his beloved monsters, he sets out with an infinitely evolving slime. Unbeknownst to him, he will also create a new city with new companions and his distant beloved monsters in this new land.