The Prime Minister’s Darling - Chapter 158 - : 111 Slap in the Face (Second Update)_3

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

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

On the brink of destruction, I regained consciousness and found myself back in the past, 20 years ago. In order to have a peaceful retirement, I must prevent the impending doom.

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates