Diamond Indestructible Stronghold Master

Summary

"I am a player of the martial arts metaverse, but I unexpectedly reincarnated as an NPC in the game. Not only do I retain memories from my previous life, but I have also become an ultra-powerful antagonist NPC. Surprisingly, just like the players, I can fight monsters, level up, and collect treasures! In this life, I'm going to become the ultimate king of imitation!"