MTL - After the Rebirth, the Male God Have Seen Me - Chapter 51

Traversing worlds with the Immortal Sword slaying demons, it was not until a monkey who claimed to be the Monkey King appeared before Lu Yu that he realized he had come to the world of Journey to the West. Striving for supremacy along the Human Path, the secrets of Journey to the West unrevealed, cutting off heaven and earth, the Three Realms were isolated.

There is only one Magi Craft Meister in the world. After the death of the last Meister over one thousand years ago, Jin Nidou was transported to another world in order to succeed her will.

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

[Congratulations! You are the Pioneer of the Mutation Abyss. Brace yourself - The Apocalypse begins now…][Main Quest: Eliminate Fellow Survivors][Description: The strong will thrive, and the weak will perish]Theo was never lucky. Bullied for his appearance and always underestimated, he lived his life as a pushover. But everything changed the night a meteorite struck him. His life takes a drastic turn.Chosen by the Mutation Abyss, he gains access to a mysterious system, granting him an evolutionary advantage.The world is doomed. An infection is spreading, turning the world into a deadly battleground. As the human Infectees mutate and portals to unknown realms open, otherworldly forces threaten humanity’s survival.Theo must harness his new abilities to survive in this brutal world. But in a place where strength is everything, will Theo keep his humanity, or become something worse?