Buttercup's Favorite

I'm not using names because i know names r confusing everyone. So the summary is probably

So basically this black hair dude (jaegeon) been in love with the blondie (jooyoung) since childhood and he's jealous of our main uke (dooyoon) but also uses his condition as a way of keeping blondie to himself. He has nux with him who look exactly like the blondie probably his dad or twin? And he uses the situation by asking blondie to sleep with him every time blondie needs the blood of nux for our main uke boi.
Now that our main uke has got this worst, he's planning to finally get rid of him and take blondie to himself by force once n for all because he's fuked up in the head?

And we learned our uke's father was also half breed who died early probably because of similar reasons.

Meanwhile, the director seme (kangwoo) shows up at the blondie's door.