Natsumi is Akari's childhood friend. Unlike Akari, who attends university, Natsumi has been working in her family's auto repair shop since she was in high school. Akari's red hair gives Sorawo the impression that she is a delinquent, along with Natsumi's blunt manner of speaking. In exchange for the help received in dealing with the Sannuki-san apparition, Natsumi agrees to modify Sorawo and Toriko's AP-1 vehicle.