Gonna put a bit of rewrites for the KS x YS au here in case I don't write them on the ellipsus doc, I think not since I'll def just change some things later out of self indulgement
I like taking advantage of the main story to make Taeho and Inyeon actual close friends, most important is that, I think Sangwoo and Jieun did have something similar to a relationship, not official as far as I know, but by the way they showed how they interacted the first time meeting her it was obvious they already had a thing going on.
Unlike in the manwha, I'd like the relationship status to form over time hand to hand with the main plot rather than just seeing what Hakneung sees while being kidnapped, which is the same reason we don't see much from Min Jieun backstory since the story at first is only seen in Yoon Bum's eyes, she's the key to form the tension that develops the plot over time until Sangwoo eventually recieves karma, but besides that she doesn't have enough highlight to call her a deuteragonist.
Inyeon as a deuteragonist, would be much more performative, I imagine, unlike her original counterpart who's more "blank"...? . She was largely guided by how her mother behaves and behaved in her younger years to create her own mask; even though her beliefs and values align more with those of her father, people often say that she is an exact copy of her mother, since the only ones who can see her act naturally are her close friends.
Taeho would initially take a liking to her for the same reason: she seemed like a typical good-looking girl, thinking of her as a relatively easy target. However, around the same time he met Inyeon, he also had another girl as a target, the first one seen being kidnapped from his house in the first chapters of the manga! This means that Inyeon was someone he already knew when he killed the other girl, whom he barely remembers, unlike Sangwoo who was just meeting Jieun after killing the previous girl. I like to think that besides romance, Inyeon is even more fascinated by dark romance and morbidity. She enjoys fantasizing even more about the concept of an obsessive-compulsive romance partner in fiction for the typical reason that it's a more intense and distorted version of intense love- plus, thats why I think the moment she doesn't mind Taeho's out-of-place comments is an open door for him to also fantazise about his desires...
Already mentioned it, he would mask and pretend multiple times until he happened, out of irritation, to act like himself which happened to work greatly for him.
He'd give her hints of alikes of these topics too subtly the moment he became a close friend, they slowly gain this quite unique bond where even if not saying it out loud, he does like what she had to say about these ""love"" stories, such specific stuff that he would finally ask her one time if she'd like HIM to do that to her. That would caught her out of guard but nevertheless, since he's pretty akward despite acting like he's not (in her words), she starts to find it amusing, his ways to add to conversations the moment he stops pretending are something she really is eventually attracted to .
She sees it as a way of him feeding her dumb fantasies, she doesn't think he actually means any of the sort, that "I'd hurt you if I felt like it", which is very specific but as I said she thinks its him saying anything because of the thing she has said to him. Its kind of their weird, stupid humor thats not much of a joke coming from him. I like to imagine that at a certain point she does ask him what he'd do to her, which he would flatly say:
"I would kidnap you, take you to the basement, kill you. You would trust me so much that you would never tell anyone where you went or who you were with. It would take months to find your remains, by that time you would be nothing but bones."
Bad route for her because for him this is obviously taboo and her letting him say anything EXCITES him, it excites him to tell to her victim what he wants to do just for her to cackle about it and just tell him she'd rather be him than anyone else wich so much endearement, he does love her but more important he gets overwhelmed and that makes him postpone the day of her death for the simple reason that he still wants to see her being so oblivious about him.
But yeah... he also gets flustered like a princess, in his deranged way, so he from the outside looks cute to her when saying something creepy then looking away when he actually meant it
