Diamond Indestructible Stronghold Master is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

“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!”