I mean, he wasn't bad, he did stop and helped MC (he even borrowed him his own dildo cmon he has to be a good guy XD). In other mangas -omegaverse- it's pretty common that "bad jealous omega" incites "faceless" semes to gang rape uke. But he didn't. So I think he's just mischievous in a good way?
I'm wondering about one thing, in the beginning doyoon's eyes were black and after few chapters they became gray, light blue. Is there a reason or was it just an author's vision?
Idk but there is a vamp I think what looks like the director but the director has light blue eyes and the vamp version has a grey and dark blue I think
Change in art style. Thats all, the first fee chapts have a different style if you notice, and they decided to make his eyecolour more prominent. Also the director and look alike vampire actually look quiet different if you put them next to each other
I thought it was because doyoon was just getting gradually weaker and he was struggling to keep up his human appearance, which made his eyes lighter and lighter to the point of getting red.
In my headcanon one of them was switched at birth >_<