The Demon King's Cheat System (Colored)

The Demon King's Cheat System (Colored) summary: The world was suddenly flooded with countless dungeons, ushering in the "Dungeon Era" or the "Age of Dungeons and Monsters" for mankind. Aldslay, who ruled an abyss-level dungeon, was dishonorably defeated by humans who resorted to unfair tactics. Motivated by rage and disbelief, Aldslay was reborn as a novice player and unwittingly triggered the "Boss Player System," which empowered him to conquer multiple dungeons and ascend to the rank of Dungeon Master. And thus, his journey for vengeance commenced.