Responses
i just reread the first chapter and you're right he is 18 in korean age! Im sorry I messed up his age because they become legal adults when they're 20 and I remembered they spent two years together as house mates!! Checked the age gap and it's still 12 years, so 18 and 30 I'm sorry it might seem better from a western point of view but you become an adult when you're 20 in korea!!

I read in korean on booktoki if anyone is interested and I don't think there's a full version in english anywhere yet.
Sooooo... I think it was ok. Personally I don't really like these kind of stories with minor lead and older adult lead who is a parent role to the minor and then later have a relationship. If you're like me you'll probably think this is borderline or straight up grooming... but then again I'm 100% not in a position to judge anyone because even if I don't really like these I still read these kind of stories, and have read worse.
If you're familiar, this isn't like A tree without roots even though from the premise it may seem like it. Kwon Sejin isn't like Heeso AT ALL, he isn't a psycho with trauma. I like to express this a lot because the reason Sejin isn't like Heeso is because he had Cheon Seju, other than his mother. Cheon Seju was always by his side and helped him grow into an adult kind and responsible. Also I want to say that Cheon Seju never allowed himself and Sejin to express feelings and form other type of relationship (other than guardian and minor) until Sejin was 20. There isn't any type of rape in this story, every sexual act they have is consensual and when they're both adults.
The novel was quite lengthy, yet I felt like there were a lot of things missing. There isn't any time skip so we all saw Kwon Sejin grow with Cheon Seju. They start dating at the very end of the novel. So if their romance isn't the main theme, what is it? Even the gang organisation plays a more minor role than what it seems. So.. the main theme is family and forgiveness. Which is what bothered me the most because the author clearly kept pushing the found family trope (which I love LOVE don't get me wrong) yet at the end they still made Sejin and Seju be in a sexual relationship, with weird situations sprinkled now and then that constantly reminds you that they are a FAMILY, like son and father or brothers, especially when Seju kept saying until the end how Sejin acts like a baby and how younger he is. So it made me feel a little uncomfortable.
I still think its not the worst with these kind of theme (adultxminor) but it's not the best either. I kind of wanted they stayed with a platonic relationship, given how the author was pushing the family theme. And yeah that's what I wanted to say, read this at your own risk. The criminal organisation theme was very present but somehow it wasn't important at all, which made it seem so rushed, as if they author was planning another arc but ended up closing with a strangely very good ending on every single front.
ps. If you're interested Kwon Sejin is ofc the top and Cheon Seju the bottom, even though he had always been on top. Their age gap is 12 years, they met when they were 16 and 28 [edit: its 18 and 30! Legal adult in south korea is 20]. Smut is very good especially if you love like me the experienced slutty bottom trope.