I'm still confused about the uke and blond guy's relationship, and why red hair dude appea...

Uke is a prostitute and is selling his body to pay off his father's debt that was passed onto him.

Blondie probably likes him sexually but is probable that he's a caretaker of people who has debts hence why Uke and blondie knows each other.

and Red Hair is still a mystery. We don't know anything about him other than prostitutes are a trigger of his and his teacher was a prostitute too.

Thank you so much for explaining, it's much clearer now!!