Do we know for sure he is forced to do all that! I mean maybe he enjoys it, who knows?!
Could be but if he really was in a consensual whatever type of relationship with the old man and enjoyed that treatment, he wouldn't be so afraid of being found out that he had sex with another man and he wouldn't cry and ask for forgiveness in such desperate manner, like in a trance. Yesung's definitely being exploited (groomed) but probably he thinks that is normal and it's the only way for him to feel truly excited. We need to see the after effect of those drugs too...
Honestly it could be, but sometimes he also acts vicious and weird, to be honest they all seem pretty weird to me at some point i actually felt like the old man and even him werent human.
What the... so he's a drug user? At least when he is fighting. Good lord... this poor man is abused in every angle. Now I really want to know why, why he's so willing to do all that for the old man. He's his 'master' now, ok, but why he goes to such lengths for him, how they met and why he's so loyal. I don't want to see them have sex, what we were showed was enough to show the power he has over Yesung, but it's not clear if the old man can have relations with him too. Maybe he is impotent and that's why he uses art, and his hands and toys, as an outlet? Anyway, Old man really has Yesung in the palm of his hand.
And Gyeol... he's fighting Yesung near the future but, I feel like Gyeol wanted to have a relationship with Yesung, a kinky one, but kinda a normal one, go on dates and stuff, but he got the craziest mf he could find. I suppose birds of a feather really flock together. They're meant to find each other at some point and even if Gyeol is another problem on his own, his sex drive, a bit of anger issues and lack of control, still he cares for Yesung. A lot. It could be him lusting after Yesung, but there are feelings that motivates Gyeol to want to help him even if nobody asked for his intervention. Let's see how this goes.