Devil Slave (Satan system) - Chapter 6 First Side Quest

When a young woman is killed in a traffic accident on her way home from work at a tax bureau, she suddenly finds herself transported to the world of the otome game she was playing the night before – but instead of the heroine, she’s been reincarnated as the bad guy! Using her knowledge of the game, “Iris” manages to avert personal disaster and decides to rebuild her life with her modern-day economic know-how. This is one mean girl who isn’t going to let her perceived reputation stop her from being a heroine!

She, a renowned assassin of the 21st century, actually crossed over to become Su Manor’s most useless good-for-nothing Fourth Miss.

He, Jin Empire’s imperial highness, was an emotionless overbearing demonic tyrant with unrivaled talent.

Everyone knew that she was idiotic and good-for-nothing and bullied her as they pleased. But only he, the overbearing tyrant with the discerning eye, wouldn’t let go of her even if his life depended on it.

For the time being, let’s just see how the stubborn versus stubborn clash and play out in this good show of the chaser and the chased.

A dancer who was killed by a serial murderer found himself occupying the body and taking on the life of Brian Morse, a patient with anti-social personality disorder. As Brian, he has the look, he has the brain, he has the charisma, but he also has something that somehow always attracts psychopaths…[The story mentions 3 reality shows and crossovers with the American drama series Dexter. SLASH]

- Description from Novelupdates

The most feared Assassin in the world died because of vengeance.