There are three separate couples. There's no love triangles or evil second female lead.
hiii I'm looking for a couple where the girl likes the guy first maybe he doesn't even know her feelings or like most of the time he has a crush on someone else.
Sorry but this was a mess I don't like body switch or body possession as the male lead fall for the girl who is not really the lead girl. In this case not even the girl who was in love with him first stays with him, yes she was obsessed but it was her in love not the alien girl.
If you looking for a drama because of romance I wouldn't recommend this. Is there couples hmmm yes but not the romance I was looking for. Is more focus in revenge and bread.
The girl in the wall has short hair Bong Yi has long hair :)
Yeah true but from my observations It was shorter than Bong Yi like hers is under her breast. The girl in the wall it was shoulder length. I stopped the frame to see. But I get you and respect your opinion.
I know it's probably because of her guilt for being involved with Han Seo Joon's murders that she didn't return…
Actually it's exactly like this " I pitied you for suffering because you were a murderer's son. I thought you were similar to me." Either I get it as she is the daughter of a murderer or she thought he was a psycho and she is one too?
1 
Like the characters names
I'm looking for a couple where the girl likes the guy first maybe he doesn't even know her feelings or like most of the time he has a crush on someone else.
I don't like body switch or body possession as the male lead fall for the girl who is not really the lead girl. In this case not even the girl who was in love with him first stays with him, yes she was obsessed but it was her in love not the alien girl.
Either I get it as she is the daughter of a murderer or she thought he was a psycho and she is one too?