Tensei Shitara Slime Datta Ken (WN) - Chapter 286

A relentless young man, a shadow of a dragon soul sword, a legendary immortal saga.Who will be the peak in the battle for imperial supremacy, only I, Lin Xuan, despise all living!

Chen Shen traveled to a world of immortals and became the corpse collector of the Xianzong, burying the dead disciples every day.

To bury the disciples of the seventh level of Qi training, to obtain their immortal skills and experience, and to obtain part of their spiritual roots.

To bury the disciples of Daofeng’s inner disciples in the array, get the spirit-gathering array, the killing array, and the experience of the array.

Bury alchemy masters, get Peiyuan alchemy recipes, build foundation alchemy recipes, and get alchemy master experience packs.

Bury super geniuses, complete spiritual roots, and achieve heavenly spiritual roots…

Twenty years later, Chen Shen, the body collector who has grown into a Jindan Zhenjun but is still low-key, discovered that the corpses sent this time were unusual, as if they were from the whole sect!

- Description from novelbuddy

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

A man is reborn into the world of Avatar: The Last Air Bender as a waterbender from Katara's tribe. Best of all, he was the same age as her, and he had a system with him to help.He knows the future and a system that lets him continuously get stronger by completing quests or long-term missions, as well as giving him the ability to copy abilities from others for himself. He will become invincible in the world of Avatar, even more so than the Avatar himself.