The Discarded Harem Member’s Counterattack [Portal Fantasy Revenge Tale]

A tale as old as time. A female love interest suddenly turns into a whining, vapid woman jealous of the oh-so-powerful main guy's harem. She becomes a mockery of whoever she used to be to serve the plot. And when she tries to disrupt the harem and fails, she falls to her knees begging for mercy only to die. No one cares and the novel acts like she never existed. Eighteen-year-old Leila is crushed when this happens to her favorite book character, a viper-like assassin named Cleo.

Angered she writes a bad review on the web serial and heads to bed wishing she hadn't wasted her time on such garbage. Too bad her review reaches the isekai gods themselves and she is thrown into the novel she had just trashed. Forced to live as Cleo in order to complete a "counterattack" against the novel's characters, Leila says fuck it and decides to raise some hell. Who cares about the predetermined plot, the harem, and the prince?! All she wants is to get revenge and get back home.

[Daily updates until I run out of chapters, inspired by the counterattack manwha Cheating Men Must Die.]