The Great Mage Returns After 4000 Years (Web Novel KR) - Vol 1 Chapter 6: To Change Overnight (2)

"There is a thin line between poison and medicine, and I shall make you dance on it!"

When Song Qinghan woke up, he found that he had not only transmigrated into another world, but also… had a ball in his stomach. He thought the original owner of this body had left a total mess to him. But it turned out there was a piece of precious jade hidden in it. Looking at the six-pack abs of Wu Dahu, he rubbed his hands with great excitement. Farming, your job! Hunting, your job! Giving birth, ahem, you worked hard! But surgery… leave it to me!

Among the demons, the supreme ones are called “Great Saints.”

A young man leaves his mountain village and travels around the world. By unceasing efforts, he finally becomes a legend of the age.

- Description from Novelupdates

This is the tale of an earthling, who transmigrated as a dying third-rate god but somehow rose through the ranks, gaining followers and eventually causing the Fourth Great Apocalypse.