I guess you have to drop it cause
<SPOILER>
ML is Ruve, past and present timeline. There are plenty of spoilers in the comments, including the real reason of the past timeline. Short story, it was the duke's fault, tia, ruve, and the bitch was poisoned.
If you don't like it, drop it, cause if you want tia to end up with carsein or the green hair dude, that's not gonna happen.
Is Ruve the prince?
Yeah
They're just mad because tia and ruve is canon can't do anything about it ε=ε=(ノ≧∇≦)ノ
Your envy does not equate to what you did to her in the past. You killed her father. That trumps everything she did and by the way she did it unknowingly which just makes what you did worse. She changed her ways this time round and she gained results from it (her father openly showing love). I hope she doesnt end up with him still. I dont know what the author can do to make him look favourable now if he is indeed the ML with Tia.