Pet King - Chapter 1784

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

Beast Taming: I Can Evolve Indefinitely

QiLeren had just cleared the bad ending of «The Nightmare Games» when his laptop died well before its time. His luck seemed to follow him as he was transported, along with the other passengers, to a hospital following an accident between his bus and a truck. Upon waking in a transfusion hall rather than a ward, QiLeren felt a familiar sense of dread as he took in the hospital that held no trace of other people…

Book 1 of a Trilogy

- Description from Novelupdates