It could be considered an aspect of yaoi but once again sangwoo doesn’t sleep with yoonbum because he likes him … he sleeps with him because he reminds him of his mother which is an outlet to get his anger out. Sangwoo also states that he isn’t interested in guys and the author confirms he’s straight and that this isn’t a bl T_T i know it’s confusing since they have sex but like I said sangwoo is straight and has no romantic feelings for yoonbum.
Sex isnt really the same as rape so im not sure, Its a psychological horror that has rape between two males but only one of them is homosexual. "Yaoi is a Japanese term that refers to a genre of fictional media, such as manga, anime, and novels, which primarily depicts romantic or sexual relationships between male characters. It typically targets a female audience and often explores themes of love, desire, and emotional connections within same-sex relationships", their relationship was sexually abusive so it could apply.

As someone who’s overanalyzed Killing Stalking and has read it over 3 times, please stop calling this a yaoi T_T It’s not a romance but is one of the best psychological manhwas I’ve read that doesn’t just consist of rape over and over again without an actual plot… this shows a story of two people who are obviously not mentally well and this should never be counted as a yaoi nor should it be considered anything near a romance