Spoilers
Sorry but no Jieun was a part of people who kill Tia with duke Jenna ,the past Ruve was drugged and manipulated like a puppet(not a real evil) ... Yep the real evil is Duke Jenna with all the others nobles but Jieun was not drugged before just manipulated and scared from this world but now she came back and want to get her revenge against everyone if she was really nice she could have taken the other option to came back to her world and forget everything (God gave her two choices) but she preferred to came back to prove them that she is better and get her revenge ...
For me she deserved to be punished from what she did before and know but she will not have a bad ending because at the end she will help Tia (I think not sure for this part) and will be spared..
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I forgot about that, omg I think I got confused with another isekai character. You are right, these 'good heroines' are getting out of hand.
Haha yes she is the bad isekai that we got its shame to us because she came from our world but its fresh to see that the isekai character is bad for once ...
Well, we got to the tedious part of the story...sssspoilers
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There will be intrigue, some plot twists, reveals, but we are waaay far from the end.
Don't hate Jieun, she only wants to prove to herself that she's a capable person. She came back from the future like Tia. The real villain here, besides Duke Jenna (the old and evil man), is past Ruve (prince/present emperor).