Kizamaro Saishouin attends Echo Ridge Elementary School as a classmate of Subaru Hoshikawa. He forms part of a determined trio alongside Luna Shirogane and Gonta Ushijima, actively working to persuade the aloof Subaru to end his self-imposed isolation and return to regular classes. Kizamaro frequently expresses frustration at Subaru's distance, interpreting it as being looked down upon, a feeling amplified by Kizamaro's notably short stature compared to their peers.

Within the group dynamic, Kizamaro consistently fulfills the role of correcting factual errors made by others, particularly the physically imposing Gonta. This establishes Kizamaro as the analytical and detail-oriented counterpoint, their interactions often following a comedic pattern where he provides logical corrections.

Following the resolution of the Mu continent crisis, Kizamaro attends a concert by Misora Hibiki alongside Subaru, Luna, Gonta, and other classmates.