Cultivator vs. Galaxy: Rebirth in a World of Mechas - Chapter 12: ch William in the Mirror

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

“Even if this universe is truly nothing more than a brutal bloody shadowy forest, we Cultivators will burn all that we have just to give off a single weak flickering spark in the darkness!

A teenager who unexpectedly gets transported to the modern world from ‘the world of the immortals’ . He finds himself in the body of an ordinary guy. He wants to go back to his world and for that, he will have to practice to get stronger and investigate the reason why and how he crossed through to this world.