Kantan na Monitor desu - Attraction 04: Sudden Death Old Maid

[You have entered the dungeon at Gwachun Station’s 1st Exit.] When former high school student Kang Woojin finds himself returned back to Earth after being forcibly summoned to a foreign planet for 20 years, he soon finds that Earth is not the same, normal place as he once remembered it to be.

My Beautiful Teacher tells the story of a university graduate Qin Chao who can’t seem to find a job and is in a downward spiral in his life. Then one night as he walks home from another failed job interview, a vase hits his head, making him get possessed by an old and powerful evil spirit sealed in that vase and following another incidents, inadvertently saved a mysterious university teacher Su Ji, thereby opening his path to cultivation, he also manages to get a job as a security guard at Guangyuan School. A series of adventures then took place as he deals with all kinds of supernatural beings.

- Description from Novelupdates

Once upon a time, an Alchemist Grandmaster from the World of Immortals accidentally took possession of a playboy, who hailed from a rich and powerful family, and became a student in the middle of his midterms.

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.