@RobinMedea
I am in no way saying he is a good person. But she is literally a one-track mind and not giving him any chance to change her mind, nor giving the original female MC any change of mind either despite her actions not matching what she was like in the book. I really don't know for what reason the king refuses to give Ignis the throne and gives his long lost son the position. And the MC really doesn't give any of this much thought either. She doesn't think about the reasons behind anything.
Despite being villainous, Ignis offered a cure for MC's father, she didn't threaten to kill him. He completely gives her the choice himself, and even agrees with the "no killing" rule. But somehow that doesn't change her perception of him even a little. The alternatives he could have done is just threaten to reveal her father's health to the public or straight up kill him (of course, that would never make her loyal to him).
Also other alternatives, if Ignis just killed the original female lead and Letio prior to the king crowing Letio, then that would also prevent MC's death. Since Letio is the one who killed her. Who says he needs to keep the MC alive just because the book says he's a good guy.
Anyways, yeah, the point is, this MC really sucks and I can't follow her logic.