Ryo is just sinking lower and lower. I'm really curious if Kurogawa is going to stop him or even care about this at all. Where does forcing someone into a fight by raping their girlfriend fit into his philosophy? Or Ryo's, for that matter. Ryo only cares about the fight, about winning and getting stronger. Losing, not fighting, not progressing upwards is the same as being killed to him. He's still in his parent's home, he's still in that jail cell with his rapists, and he still thinks that he'll die if he stops fighting. We've already seen him descend into sexual violence after being raped himself. Martial arts saved him from his rapists and abusers, but now he's no better than them.
I keep going back to his sister saying she understood why he killed their parents. I think he was being abused, in some way. She said "you had to kill them, or you would've died yourself" or something like that. And that's been who Ryo is since the beginning. A broken thing that will do horrific things to survive, that will not allow himself to be killed. But now, his parents are dead, and he's free from his abusers in jail. No one is trying to hurt him, but he's still fighting. He was brutalized by those stronger than him, and now he can't stop picking fights with bigger and stronger opponents. But Naoto is a professional heavyweight fighter and Ryo (lightweight) isn't even a blip on his radar. So Ryo might end up resorting to sexual violence just to force Naoto into a confrontation.
I don't know why today I was reminded of a manga that, just thinking about it, makes me tremble. No, it's not horror, in the strict sense of the genre, but I could classify it that way because of all the things that happen from the beginning. I mean SHAMO by Izo Hashimoto and Akio Tanaka, a manga that talks about violence in all its forms through the protagonist, Ryo, a boy sent to prison who learns martial arts and evolves into a monster. Is very good! But I also think you have to have the stomach to read it.