Natsumi Koshigaya

As the energetic younger sister of Komari, this middle school freshman is a quintessential tomboy with a lovable, airheaded personality. Though she brings a spirited presence to her daily life, she often struggles with her schoolwork and maintains rather poor academic grades. Her carefree nature and clumsy charm make her a standout character within her family dynamic, providing a lighthearted contrast to her older sibling's more serious demeanor.