Literally tho, like we know he has a mental disorder, but seeing pieces of it in the actual manhwa instead of the author just telling us is insane. Like when he said that In-Seob is a "sucker for these Small domestic gestures" so he does them to manipulate him. Like physiological manipulation is unsettling
This is the reason why i like him as a character because the author wrote him realistically, you can see him charming other people and being awful at the same time not that other manhwas don't do that but here idk, it's just it has more impact.
He's scary because he's the type of person that can exist in real life. A lot of readers are saying that the writing is bad but for me it's actually okay and good.
I've read BLs of characters doing worse than he's done and somehow he's the scariest BL character ever. He's so unsettling.