The beginning was really good and now is still good. It wasn’t supposed to be romance anyways, so the thrill was what kept the readers going and the rating high. But after they added romance to the fenre, pretty sure that’s why it feels like this now. Because before, we look forward to the thrilling part of the ghost chasing the bastards and helping her. But I do agree with you, they don’t have a good enough chemistry
Hm I guess I can see why he's naturally attached through that but he's only had one goal. It was to use her, so when he's randomly caring about every word she says without any proper build up to how their relationship developed into something of affection it's like wtf. Especially deep in his unconsciousness it made no sense for him to be so deeply obsessed with her to the point of wanting her as his lifelong partner. Even the guy who betrayed ML first makes more sense as to why he could be attached to someone. He discovered ML first and even gave him a name, actual meaningful moments.

ok here are my thoughts after reading this very high rated manhwa. It's...bland. Characters are what really make up a story so when you have a dumb main character and a mysterious obsessive ml, and literally NO good characters except Geonwoo, it makes it unenjoyable. The MC and ML literally have NO chemistry at all. I just don't understand why he cares for her so much when nothing special even happened between the two?? I understand why MC is the way she is, not gonna argue with that. She's just not fun to read but I liked when she didn't drag Geonwoo down with her. And maybe we could get away with glazing ml but he's not even a human of ever was, his true form is an ugly entity
Overall, plot is a good concept and art is amazing I just think we could've gotten better chemistry between the two characters and better characters!
But the manhwa is also interesting enough to keep readers intrigued like me, just disappointing enough to question the high rating and glaze. Hopefully we see some development!