MTL - Unlimited Cycles of Death - Chapter 24 Iris 24┃ has a profound understanding of the killer.

In the era of universal mechas, people can go to the endless abyss, collect materials, strengthen and forge their own mechas, and master the power of destroying the world.

Jiang Chen traveled through time and awakened his talent [Immortal Unarmed]. Once the mecha is broken, he can permanently absorb its power and receive multiple bonuses.

…

At the bottom of the abyss, when the Old Demon God finally broke the Titan mecha with great effort, a hand stretched out from the fragments and held down its head.

“Congratulations, you have unlocked my limiter.”

- Description from novelbuddy

A lecherous army special task force soldier from 21st-century Hong Kong is selected to travel back in time, choosing to go to the Chinese Warring States Period. Unfortunately, the time machine runs into an error during the experiment. With no foreseeable way to return to the present, he must use his combat skills and knowledge of history to thrive in his new life in the year 251 BC.

This is a strange and inexplicable world…Mountains, water, stones, flowers, grass, trees, wood, the Sun, moonlight, stars… All creation under the Heavens and Earths are sources of energy. In this world, there are all the classics from his previous world, but there is a new addition: The Law of Dao. Fang Zhengzhi was conflicted. I can obtain power from reading books? Should I read Tao Te Ching first? Or should I read The Art of Becoming Invisible? What about the Analects of Confucius or… The Golden Lotus? With The Law Of Dao as his foundation, can Fang Zhengzhi master the Dao of All Creation and open the gate of God?

My disciple, whom I raised and cherished with my whole heart…That same disciple has returned and is trying to kill me.“Before you fall, before you cease to be my idol, my hero, my sun, I will kill you with my own hands. For your honor!”Just wait for a while…I’ll bring you back to your senses.