Responses
Idk if you still want an answer to your question, but here is it anyways: in the first five novels that were published around a decade ago (I think?) and that this manhwa is based on, there wasn't anyone beside Zhenya who forced themselves on Taekjoo. I'm not counting Sergei whom you already seen of you read first season of the manhwa, because it was brief and unsuccessful. So yeah, it was only Zhenya. Now, the next batch of the novels (the new ones) apparently contains scenes of another man s/a of Taekjoo.
This has to be one of the most involved and interesting Yaios I've read in a while (It's definitely more of a Mystery/Action). A lot of people are hating on this story because of the S.A scene but... this webtoon wasn't glorifying the action. Rape is Terrible. And it was framed as such, from Taekjoo reaction and the plot that followed I say the author handled it fairly well.
Sure, he could have been more tormented but, would that really match his character? His in situation where his forced to keep pushing forward, fronting his hatred for Zhenya is his way of doing just that. Moving forward, and that's all grief is.
The author wanted us to believe Zhenya was a Deranged, Rich, Violent, Asshole. And that scene was how she felt would best get everyone there, and it worked.