A Hentai System in the World of Danmachi - Chapter 54 - 53 - It works better on "NPCs".

Chen Chao dreamt of becoming a powerful immortal cultivator, flying on his sword and vanquishing enemies with daoist magic. His hopes were dashed when he discovered that he had absolutely no talent for immortal cultivation.

Refusing to submit to his fate, Chen Chao joined the ranks of countless other talentless martial artists and embarked on the path of martial cultivation, a path scorned by the immortal cultivators.

In this era of strife where martial cultivators, immortal cultivators, and demonic cultivators wrestled for hegemony, Chen Chao will either rise to the top or fall into eternal damnation.

I had to take him home and raise him. There was no bathtub or a large basin at home, so I had to put him in the washing machine for the time being.

It was an hour later before I remembered it again, by which he had been washed extremely clean.

- Description from Novelupdates

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

Damien Rothschild, an immortal who has lived life to the fullest for the past four hundred years, is visited by a mysterious woman who reveals the many depravities of his mischievous brother in another world.To save his brother, Damien must first travel to this other realm. However, the path becomes treacherous as he is tricked and loses everything he once had. Now, he must navigate this new world in search of his brother.This story follows a man who was granted the gift of immortality, allowing him to rise to the very pinnacle of the human race—until he was stripped of everything he held dear in a desperate attempt to save the only thing he ever truly loved.