Boyfriend of Ayuko Oka
" Tomorrow, I will get to see Oka, for the first time, wearing her school swimsuit during girl's PE swim class . . . . "
Kouhei Ueno is Akria Tsubaki 's friend and Ayuko Oka's boyfriend. When Tsubaki first walked in on him and Oka kissing, Ueno asked him to keep their relationship a secret, as Ueno is rather shy about it. He helps Tsubaki by providing advice about romantic relationships, unaware that Tsubaki is already in a relationship with Urabe. But when he finally finds out, he seems to approve, realizing that Oka and himself are more advanced in their relationship than Urabe and Tsubaki.
Ueno is shown to be very jealous of Oka, and doesn't like the idea of taking her to the beach, since she prefers to wear a very reveling cream-colored bikini. She also likes to dress in casual clothes that are a bit too daring and provocative, but he also tries to keep some control by suggesting that she dress in more conservative styles, in order to avoid other boys from flirting with her.
Although Oka has the abilities to form a drool bond, and already has a romantic girlfriend/boyfriend relationship with Ueno, they do not have, and can never form, a drool routine between them, as Ueno does not have the ability to send, receive, or process drool. Because of this, or in spite of this, Ueno falls deeply in love with Oka, and highly values his relationship with her.