From Idler to Tech Tycoon: Earth - Chapter 61: Drive

I came from hell, looking for redemption! –“Revelation”
…………
What is redemption?
I think it should be a process in which a good person becomes bad and then becomes good again.
It’s like our clean birth, contaminated by the dust of one life, and then clean death.
Well, this is just a story. …

- Description from Uukanshu

Lee Se-Hoon, the blacksmith of humanity’s last desperate united force, fought against the demons until the very end. However, the result was mutual destruction, with the world coming to an end. The moment he took his own life over that futile conclusion—

“…What is this?”

He had regressed to his days as a candidate at the hero training institution, Babel Academy. Having obtained a second chance, he swore to use anything as material to gain victory this time. Anything at all!

The Yanhuang Ancient Domain, vast without end, gave birth to many Celestials and Demons of antiquity tore Heaven and Earth apart and surpassed the control of the 3 Realms and 5 Elements over the endless years it has existed. Numerous Gods, more than ten thousand races, and humans born with a God class body have also come out from the Domain, traveling through the nether, warping Yin and Yang, omnipotent.

This is a story about the protagonist getting the system, going crazy in the biochemical apocalypse, producing aircraft and tanks, destroying zombies, saving good people and killing bad people.

- Description from novelbuddy