HP: The Arcane Thief - Chapter 33: Daphne's Problem

I once believed I was the heroine of a modern fairytale, blessed with beauty, wealth, intelligence, and a powerful legacy. Men adored me, women envied me, and I was engaged to the most desirable man, Cole Fay. My life seemed perfect, a dream where I held the starring role. But on my eighteenth birthday, that illusion crumbled. The truth hit me hard: I wasn’t the protagonist, nor even the villain or a side character. I was just cannon fodder, a disposable part of someone else’s story. But when fate recognized the cruel joke of my life, I was granted a second chance. This time, I’ll write my own story, living for myself. And this time . . . I will never love you again.

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

One day I got a younger sister.Only I know her true identity.

Over a million years ago, the first human contracted with the first Spirit. Ever since then, Spirit use has become commonplace. Humans used Spirits to carry items and start fires. Eventually, even start wars. Thousands upon thousands of years past and one day, one human did the impossible. He transcended his mortality and ascended to the realm above.