He is Nono's and Akira's fellow club member, as well as a freshman himself. He is good friends with Nono. He used to attend elementary school with Kiyoshi, and thus knows of his terrible personality.
He explains that Shiriya once killed a jumper who was better than he was. He therefore is scared of Kiyoshi and does not want to have anything to do with him, even going as far as stating he will not try to jump farther than him so he won't get into problems.