Rest in a Demon's Embrace [BL] - Chapter 165

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

Abandoned by Fate, but Chosen by Chaos.A world where magic reigns supreme and the mightiest wizards stand at the apex.A world where one’s mana affinity, if one even had it, determines one’s status in society, whether one could soar through the skies like a dragon or remain grounded, scraping by like rats or chickens.This was the world Hal Fennec was born into.Raised in the poverty of a border village, Hal had one wish: to give his mother a better life, one free from the constant fear of beast attacks and invasions by the Fellkin.But fate seemed to be playing a cruel joke.Despite being the brightest and most confident among his peers since childhood, Hal turned out to be barely qualified to become a wizard.His natural talent, contrary to his expectations, was nowhere near enough to fulfill even his modest dream of a decent city life.But then, just when his final hope was snuffed out and the future seemed gray and bleak, a twist of fate—or more fittingly Chaos—granted him a system that would turn everything around.

Collapsed without warning, and upon awakening, he found himself back in his childhood.He thought it was a blessing from above, but unexpectedly, tumultuous changes ensued, shrouded in mystery...

In the third year of the reign of Yu State, it rained in the city of Weizhou.

Li Ang woke up in a daze, dreaming that there was a sword hidden in his head.

- Description from novelbuddy