Shinjiro Chikami, nicknamed Kamishin by protagonist Suzu Naito, is a hot-blooded and enthusiastic high school student. He single-handedly launched his school's canoe club, relentlessly pursuing inter-school athletic success to qualify for the competitive canoeing national championship, a goal he ultimately achieves.

Though occasionally airheaded, Kamishin often jokes about female classmates harboring crushes on him. This habit sparks significant personal developments, particularly with classmate Ruka Watanabe. After he jokingly accuses her of romantic feelings, he discovers she genuinely likes him. Bonding over their shared appreciation for Belle's music, Ruka promises to attend his canoe nationals. Kamishin deeply values this pledge, believing her presence guarantees his victory.

Within the virtual world "U," Kamishin's avatar manifests as an anthropomorphic dog featuring long brown fur, white cartoony eyes, elongated flappy ears, a furry snout, and a black nose, marked by a prominent scar across its right eye. Reflecting his real-world passion, this digital form perpetually carries a paddle and wears a canoe strapped to its back.

Kamishin belongs to Suzu Naito's social circle alongside classmates Shinobu Hisatake and Hiroka "Hiro" Betsuyaku. During the critical search for the abused user known as the Dragon, Kamishin partners with Ruka. Together, they analyze clues and deduce the location as Kawasaki, Kanagawa Prefecture, near Tokyo, enabling Suzu to locate and assist the individual in the real world.