Ryo Okayasu is Kairi’s older brother in Peach Girl.
According to Kairi, Ryo stole all of Kairi’s girlfriends when he was in junior high. They both dated a woman named Morika, and Ryo claims that he was dating her first, but Morika wanted to date them both, as she liked the idea of two brothers fighting over her.
Kairi claims that he was dating Morika first, and that Ryo made fun of him, calling Morika a “fat pig.”
Kairi and Ryo do not get along, as they both resent each other. Kairi hates Ryo for being a lying manipulator who steals all his girlfriends, and Ryo hates Kairi because Kairi is loved by others in a way Ryo never could be.
In Change of Heart, Momo meets Ryo and he sweet-talks her into trusting him, and even though Kairi tells Momo to stay away from him, Momo naively believes everything Ryo tells her, seeing what she believes is an older version of Kairi in him. Ryo attempts to rape Momo, and after that she understands what a horrible person Kairi’s brother is.
Ryo conducts pyramid schemes and seduces Sae into helping him. Sae ends up prostituting herself to cover inventory costs, and when Ryo is done with her, he dumps her. Sae, however, can’t get over Ryo, claiming that he’s the first person she’s really fallen in love with, so she desperately tries to keep his attention.
Ryo’s only soft spot is for Misao, the school nurse and Kairi’s former tutor. She’s the only woman he can’t get. But that was only because Misao was too shy to tell him that she liked him, too. They get together for a short while, but when Misao sees the way Ryo treats Sae, she becomes very concerned. Ryo isn’t the nice guy she thought he was. Misao dumps Ryo and he goes back to Sae, since she’s the only one who will have him. Plus, she claims to be pregnant with his child.
Ryo confesses to Sae that he doesn’t ever want to have kids, or leave any trace of his DNA on earth. He says Kairi can give their parents grandchildren, and that everybody loves Kairi. He says he’s always been jealous of Kairi, and that he hated him. Sae admits to him that she was always furiously jealous of Momo, and that maybe their jealous natures are what drew them together. Ryo had hired some goons to beat Sae up and induce a miscarriage, but he changes his mind and tries to tell his henchmen that. But they beat him up instead, having been bought out by Morika, Ryo’s bitter ex.
Sae leaps in front of Ryo to shield him, and ends up getting hit in the stomach. She is taken to the hospital where it is revealed that she was never pregnant; she had just convinced herself such because she was so desperate to be with Ryo.