Umm I mean w ain it should be pretty obvious y *cough cough training a much younger partner to suit his "tastes", pretending to someone else, using said false identity to thus fraudulently gain consent coughing cough*. Though i will say I have not read the novel for either so this is my opinion based on the manhwas only. Either way I can only see this one getting worse.
As for ash from dtr it's a bit more subtle but he is overall v pushy w karlyle's boundaries and also manipulative imo. For instance:
- doing things lyle was uncomfortable w like public kissing and rlly just pushing for physical intimacy v quickly despite saying he wanted to get to know ppl first
- that sex scene where he made lyle cry bc he didn't stop when he asked (yes ik it's meant to be an overstimulation thing and yes ik that's not the most egregious thing a seme has done in terms of consent but that's not the point)
- trying to get away w his slip ups by acting pitiful
- the barrage of compliments that feel kind of condescending and also love bomb-y right from the start (literally says that even karlyle had a cute side after calling him out before the appointed time on their SECOND proper meeting)
- introducing lyle to his sister which is VERY leading imo bc would u introduce a fuck buddy ur meant to only meet 8 times to ur sister?? And again, ash only comes to like lyle AFTER their breakup so... ?? ×2
- pretending he doesn't rmbr the new year's kiss
- being overall v controlling and using sex to kind of punish lyle (the new apartment debacle)
And this isn't even counting the dumpster fire that the side stories are but I'll stop here lol

Nahh idk what it is w this artist's longer works but both this story and dtr give me bad vibes. And by story I mean ash and ain lol. Tho ig this time it's at least the bottom giving bad vibes instead of the top but still smth abt those 2 characters just makes me uncomfortable