Aoi Nizato lives in Okinawa, where her family runs an inn. As a diligent and reliable first-year middle school student, she pitches in with daily tasks at the establishment. Aoi also enjoys sports, participating in her school's badminton club.

When the Asahigaoka group visits Okinawa, Aoi meets Natsumi Koshigaya. Their shared age and mutual enthusiasm for badminton quickly forge a bond, marking Natsumi's first friendship with a peer outside her rural circle. Aoi's consistent work ethic and helpful nature at the inn stand in contrast to Natsumi's more carefree, sometimes irresponsible demeanor, prompting Natsumi to reflect on her own habits during their time together.

After the Okinawa trip concludes, Aoi and Natsumi keep in touch. A later conversation reveals their mutual wish to reunite, demonstrating the ongoing connection between them despite the distance. This sustained friendship underscores the impact of their initial meeting.

Aoi Nizato appears solely within the Okinawa narrative arc. Her role centers on facilitating Natsumi's moment of self-reflection and representing a peer relationship distinct from Natsumi's usual social environment.