To the Love Born in the Lowest Place - Chapter 116

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

In her former life, she was robbed of her status, her looks, and her reputation.

The fat and ugly Nora Smith is the laughingstock of the town when her fiancé breaks off their engagement.He says, “The sight of your gigantic face and thunder thighs disgusts me! Don't ever pester me again!”“What an idiot.” Nora scoffs and turns around, her lips curling up into a smile.Later, when Nora successfully slims down, she returns as an astounding beauty.Her ex-fiancé comes to her bearing flowers and begs, “I was wrong, Nora. I’m willing to do anything as long as you come back to me.” Nora rests her chin in her hands and smiles as she replies, “Real men don’t dwell on the past.” Angered, he says, “You’re just a dimwit saddled with baggage that I dumped, Nora. No one will want you except me!”But following that…A young and popular singer tweets: “Nora Smith is my goddess!”An internationally renowned surgeon asks, “Are you free tonight, Nora?”Even the rich and influential hotshot whom everyone is scared of comes forward and says, ”I can take care of my wife and children myself, thank you very much.”

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