I guess the title of his popular book is partly a clue - Evaporation - everything the hands kill (or "eat") disappears.
It might be partly influenced by Stephen King's book The Shinning, like the house has something that controls people (gives them power) etc, like the hotel did to Johnny.
I just hope they do not die both at the end or Jun goes mad and Yeon controls him fully or something along those lines.
I really do not remember which chapter - it's one of their first kisses. Yeon was holding in the smoke and then kissed Jun and Jun has then completely inhaled the smoke of the cigarette. After that he bought the pack and tried to smoke himself and became weirdly obsessed with the fact that Yeon smokes and that specific brand of cigarettes. You can also look into Jun's expressions, it becomes kinda odd when they have sex, somebody said like he's on drugs on like he's controlled. He has similar expression after inhaling the smoke.
I kinda expected far more due to ratings. I did not like how half of the plot was not properly explained it just like happened, and my personal preference is not when the seme doesn't take no for an answer million times and I do not like how the uke ended up looking like a teenage character by the end. The art did improve but unfortunately it's kinda stereotypical for webtoon authors to have this style, there are a lot of webtoons with similar looking seme.
Just wanted to complain a bit, it's not a bad story tho, I can see why people like it.
If the uke had explained the situation better this would not be such a big issue.
If the seme had asked about the ex and what has happened and told the uke what he had said to him we would not have the giant drama that is going to happen soon.
If they would only do something like... talikng??? (゜ロ゜) shocking ik
It's far easier to understand if you binge read it, otherwise you will be kinda lost.