this spoiler will give a quick rundown of the series and how it ends, and why people hate the ending.
Choi Soona died and possessed the body of Edith, the villainess of some romance story (I will call it OG story from now). Edith actually isn't evil; she's abused by her family and must act in their interests or she'll be killed. Edith married Killian, second-ML of the OG story, and she was unfairly hated by him and everyone else because plot. Edith slowly changed Killian's mind and realized there's something called Author's Authority or sth (which is basically just the Author's ability to control that world), and the more she breaks it the more the Killian changes. When she finally breaks it, Killain got freed of the Author's control, she told Killian everything and they married and lived happily ever after.
Except, before she could break that thing, she was treated to tons of fucking shits by Reeze. Reeze is the original FL of the OG story, and who's actually the Author. Reeze has been looping the stories for 13 times now, and each time a new girl possessed Edith and Reeze killed them all. Every fucking bullshit thing that happened to Edith according to plots was literally just Reeze's doings: poisoning, sabotaging the yacht to kill Edith, abandoned Edith when they were kidnapped together, left her to die by torture, ACTIVELY calling Edith the spy when Edith survived and then tried to fucking execute Edith. Only thanks to Killian got freed of the Author's Authority did Edith live.
However, when the story ends, Reeze NEVER got any shits. Like, no one fucking knows she did those shits and she even married Cliff (the brother of Killain, original ML of the OG story) like nothing fucking happens. And that's it, that's the fucking ending.
Korean readers were so fucking frustrated by that stupid ending, the author had to write epilogue detailing how Reeze did some bad things and got caught, which led to the royal family sentecned her to death. Except, Edith begged them not to kill Reeze?????? What in the actual fuck?????? Thanks to Edith (what the fuck Edith?), Reeze was spared and sent to live her life in a monastery far away, and that's the end of the epilogue.
anw, the story was good until the fucking ending, the sequel was literally created because too many ppl hated the ending, and even the sequel fucking sucks