A Wild Last Boss Appeared - Chapter 15

In the tenth year after the new era, the world finally came to an end. Zhang Mu truefully waited for his death, but unexpectedly found that he had returned to ten years ago. With his memory about the future, he swore that he would change the calamitous history, saving the earth from being destroyed! Walking dead, zergs, evolvers, and various mutated animals… nothing can stop him! The first step is to retrieve his identity as an era merchant , then find all the treasures he can remember to enhance himself!

- Description from Novelupdates

He possessed the Xuan Gate Medical Arts and had fortuitously obtained a heaven-defying Spiritual Treasure!

Brutality is my style of conduct! If you can't accept that, I'm ready to fight—that's who I am!Don't mess with me, otherwise, I won't mind teaching you the meaning of “The Return of the King”!!!

It was in the year 2800 of the Midgard calendar. Back then, there was a Overlord who once reigned supreme and had reached the very brink of subduing the world.