Natsumi Hirakawa, a student in class 5-2 (seat 17), excels in athletics, consistently surpassing her peers with agile skill. Her calm, composed presence belies a relentless drive; once committed to a goal, she pursues it with unwavering focus. This determination coexists with a striking vulnerability: an intense fear of darkness that disrupts her otherwise steady demeanor.

Natsumi’s innocence reveals itself through a disregard for social conventions, often leading her to unconsciously challenge boundaries—such as attempting to undress publicly, much to her friends’ exasperation. This guileless naivety contrasts her tomboyish confidence, reflected in her preference for masculine attire and the pronoun "boku." Only in the anime’s epilogue does she briefly adopt traditionally feminine clothing, hinting at subtle shifts in self-expression.

Interactions with classmates underscore her indifference to gendered expectations. She navigates school life with straightforward pragmatism, prioritizing action over emotional reflection. Yet her nyctophobia adds layers to her persona, intertwining strength and fragility. Whether dominating sports or quietly confronting shadows, Natsumi embodies a blend of resolve and unspoken complexity, anchored by her pragmatic, goal-oriented approach to every challenge.