MTL - Dragon Who Controls Time - Chapter 7 sleep

It was in the year 2800 of the Midgard calendar. Back then, there was a Overlord who once reigned supreme and had reached the very brink of subduing the world.

Sano Yuji, a black company employee, is summoned to another world while finishing his work at home. His profession in the other world, a Monster Tamer, is considered a job that makes it difficult to become an adventurer. However, thanks to some slimes he met, which read several magical books, he gained magical powers and the second profession, Sage. Yuji acquired overwhelming power, but is he conscious of his strength? Blindly becoming unparalleled and strongest in the world!

In novels with a stud there is always a Senior Martial Brother like this:

In the early stages of the novel, his innate talent is high, his cultivation is good, his appearance is handsome, and he has an intelligent, cute younger Martial Sister as a fiancée.

In the middle stages of the novel, he is caught unprepared and defeated by a young disciple (the protagonist) in the sect who’s hardly remarkable at all. From then on, he falls from his godly altar and loses his brilliance. Even his young Martial Sister leaves him for someone else.

In the late stages of the novel, he continues to turn dark, going down the Demonic Path and becoming the major villainous boss. However, the protagonist still ruthlessly defeats him and his soul is eternally sealed.

Once Qin Mo opened his eyes, he discovered that he had become this Senior Martial Brother.

- Description from Novelupdates

When Zhou Yi woke up, he realized that he had become the prison guard of the Heaven Dungeon.Although he was fortunate enough to find a Fruit of Eternal Life, he did not possess any powers to protect himself.In a world of cultivation where demons and monsters roamed freely, Zhou Yi decided to hide himself and train for thousands of years.Time passed by quickly.The child he had freed 100 years ago had become the founder of the Great Qian Empire.The teenager he had helped 1000 years ago had become the elder of a celestial sect.The pet he had kept 10000 years ago had become the Absolute Demon King of Foreign Lands.This is the story of a normal person who has eternal life, the story of how he watched countless events unfold and eventually becomes the Supreme Celestial of Eternal Life.