Shinjiro Chikami, nicknamed Kamishin, attends high school in rural Kōchi Prefecture with Suzu Naito. A hot-blooded yet occasionally airheaded enthusiast, he independently founded the school's canoe club and actively drives it towards inter-school athletic success, ultimately qualifying for the national championship. His personality includes a tendency to jokingly suggest girls harbor crushes on him.

Within the virtual world "U," his avatar manifests as a long-furred brown dog featuring a prominent scar across the right eye, white cartoony eyes, flappy ears, and a furry snout tipped with a black nose. This canine form consistently carries a paddle and wears a canoe on its back, mirroring his real-world passion.

Kamishin shares a close friendship with Suzu, the originator of his nickname. He also develops a significant connection with classmate Ruka Watanabe. After he jokingly accuses her of romantic feelings, she confesses her genuine affection near the water. Following this confession, they bond over a mutual appreciation for Belle's music. Ruka promises to attend his canoe nationals competition, a prospect he acknowledges would strongly motivate him to win.

During the search for the Dragon's real-world identity, he assists Ruka in deducing that Kei and Tomo reside in Kawasaki, Kanagawa Prefecture, near Tokyo. His contribution aids Suzu's efforts to locate and protect the brothers.