I Need Wives For My Gacha System - Chapter 4 --

Struck down amid the battle, the Hero and Demon King meet their demise. As their souls linger on the edge of the afterlife, a mysterious force intervenes, merging their fragmented souls together with a new being. Rusty, the living armor, now affected by their memories and presence, embarks on his own quest. Will he seek revenge on those who betrayed the hero, or will he fulfill the desires of the fallen demon king? or instead, forge his own path?

Shi Jin once read a book. It was supposed to be about satisfying the desire for vengeance.

This is a story about a young man who sought to fight against his destiny. With the help from billions of Dragon Energies trapped on the Rising Dragon Pillar in his body, he emerged from the dark and quenched himself with the blood of ancient dragons. He fought the heaven with the Buddhist Art for the people he loved and built the Eternity Kingdom with his own hands. This is a story about the rise of the Martial Emperor who will rule both earth and heaven.

- Description from Novelupdates

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