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. Natsumi's red hair and blunt manner of speaking give Sorawo the impression that she is a delinquent, but Akari mentions that, like Sorawo, Natsumi is simply uncomfortable around people she doesn't know that well. In exchange for the help received in dealing with the Sannuki-san apparition, Natsumi agrees to modify Sorawo and Toriko's AP-1 vehicle.