
Honestly I have the same issue
Throughout the chapters I've been feeling bad Eclis - I get that he has an obsession and Yvonne is using that to manipulate him.
It does hurt that Penelope is shouting him out despite knowing that he was brainwashed and literally cannot function as normal person because of his feelings for her. But I also understand where she is coming from so it makes I have conflicting feelings too.

Actually no,
the whole problem with Eclis is he himself and his love
The thing is,no matter how different Mc would've approached him or would do things differently he is always gonna turn this way just because that's the way he is written in this game
His love is toxic and selfish and quite literally lethal (to the person he loves) which was foreshadowed from the beginning by the color of his love
So no matter how,the moment his love percentage gets high,his tendencies and desires to isolate Penelope would start to grow and he would harm her one way or another cause thats the way his love works and if he doesn't love her then he is just gonna harm her for the person he has this desires for(the same as the easy mode)
I don't think it's wrong to feel bad for him as a person but it's important to understand where Penelope is coming from with her actions,she isn't just mad cause of the betrayal she learned that no matter what she can't never trust Eclis and his actions because his motive is always going to be a self-serving,sinister and determental is some ways

I agree with this. He clearly needs therapy and psychiatric help. I used to feel bad for him to, but I stopped recently around the time his counter is pointed out by Pen in the prison. I didn't really think hard about why I stopped feeling pitty for him after that. Thank you for putting it all into words!
Everybody needs therapy! I'm going. ╮( ̄▽ ̄)╭
Y’all super genuine question am I allowed to feel sorry for Eclis?
Hear me out and stop here if you don’t want spoilers, but from the very beginning, as Penelope literally said, it was her actions and choices that pushed Eclis this far. It’s been a hot second since I read any chapters before 160 so I can’t exactly remember how bad Eclis is, but I can’t help but think that if Penelope had approached him differently this could have been avoided. And it still hurts knowing that Penelope knew Eclis was brainwashed and still continues to hate him for the betrayal, and it’s not just Eclis, it’s anyone who’s been brainwashed by Ivonne. Unless I’m wrong about the way they are brainwashed and they have some free will that causes them to make choices that don’t favour in helping Penelope. I can understand Penelope’s feelings a bit though cause so many times in isekai stories we see the mc accept life as it is and adapts fast, however we don’t often see how it affects their mental health. So I appreciate that in this story Penelope is show to be more vulnerable and strong at the same time which is why I understand the choices she make and why she is cold to those who are clearly brainwashed. So in that case can I really sympathize with Eclis, like at all? Maybe after all this ranting who I really feel bad for is the Eclis who shouldn’t have been in the hard mode cause he doesn’t actually meet a bad ending in that storyline, right? Aka who Eclis could have been and not who he is currently. Also if you made it this far just thought I should mention I don’t condone anything harmful that Eclis has done because Penelope is a victim, but in some way Eclis and quite a few people in this webtoon are too.