Trash Class Dungeon Lord

Kai Mercer awakened as a Dungeon Janitor, the weakest trash class in the tower. Then he discovered the hidden rule: anything the dungeon marks as waste can be claimed. Heroes take the treasure. Kai takes the broken weapons, dead monsters, failed spells, abandoned rooms, and unclaimed boss drops they leave behind. Now he is repairing traps, hiring monsters, billing arrogant heroes for damages, and turning the tutorial dungeon into his own kingdom. The tower gave him a mop. It should have checked who owns the mess.