Inside the Cave of Obscenity - Vol 3 Chapter 16: Female Scientist 3 (Aphrodisiac,

Surgeon Guan Ryo Is reborn in Naruto’s world! Enjoy his trip as he uses his knowledge of the story to find his path in this troubled world and eventually stand at the top of Konoha!

He—an enigmatic and cold-blooded soldier with a mysterious background.
She—a ruthless and bloodthirsty spy.

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

When a person dies, they either die light as a feather (aka unimportant) or heavy as Mt. Tai (aka very important).