Dungeon wo Tsukurou

A man awakens in a palace throne room holding a grimoire named “Let's Build a Dungeon.” The book informs him he has become the Demon Lord, tasked with conquering the world. Using the grimoire, he constructs dungeons, defeats human forces, and achieves global domination. Believing he can now enjoy peace, independence, and culinary pleasures, he instead faces continuous attacks from various enemies, including other demons, sword masters, and knights.