Synopsis

The protagonist is on a quest to kill secondary-class monsters when they notice the trolls are behaving unusually and are seemingly being controlled by a hidden force. Suddenly the dungeon's exit vanishes, cutting off communication with higher beings and suggesting they may be in an 'abandoned world.' A new, mutated monster appears, significantly stronger than previous enemies, and it's revealed this monster is a result of other monsters evolving due to the absence of other enemies.