Overlord (WN) - Volume 1 Chapter 15

Revenge is a dish best served cold, with dollop of whipped suffering and a sauce of acute humiliation.Karma would do anything to exact revenge on the one who was responsible for her mother's death, her father's disdain and distrust, and a miserable life.She was manipulated, maltreated, and humiliated by the one she trusted the most. Her stepsister!!Discovering she had only three days left to live, Karma would go to any length to exact revenge. Even offering herself to the scary and powerful demon overlord.A contract. Blood oath. Manipulation. Betrayal. And lots and lots of revenge.

Zhou Yu, a reclusive otaku, who did not like to go out of his house, was one day forced out of his house by a series of unexpected events.

- Description from Novelupdates

“Shit, why this guy!?”Of all the unique characters he could’ve transmigrated as, it had to be the bastard instructor.Vanitas Astrea.A third-rate middle game boss, who was dismissed from the University after severe allegations, losing his teaching profession and ultimately, exiled from the Empire.“.....How did I even get here!?”Vanitas must now circumvent his way around this new world, confront his past, mend broken relationships, and prevent looming tragedies that would lead to his demise.

Protagonist travels between different anime worlds to right wrongs and uncover his reason for being along the way.