The Silver Labyrinth

Blessed by the protection of the god of craftsmen, the main character, upon achieving the pinnacle of business, gets bored of it. Trying to be an adventurer but finding himself painfully inept, he finds out of an exceptionally weak dungeon that has an incredibly strong dungeon boss. Under the correct timing, he manages to conquer the dungeon while the boss leaves for lunch. Thus he uses his knowledge and experience in business to run a successful dungeon.