Amika Kuribayashi attends high school alongside the main characters, distinguished by her black ponytail and blue eyes. She consistently wears a school uniform with socks and a neckerchief.

She shares a close friendship with Sakurako Urushima, and together they observe and discuss the evolving relationships within their social group. The duo affectionately nicknames Ryou Ninomiya "Ro-baby." Amika joins group excursions, including a beach trip where Kimi Ninomiya accidentally bumps into her and Sakurako, resulting in an unintended kiss between the two friends.

Physical attributes dominate Amika's focus, particularly during conversations about designing clothing for Akari. She openly expresses jealousy toward Hikari's proportions while identifying with Akari's petite stature. This envy partly motivates her agreement with a theory proposing Hikari and Akari’s non-human origins during a discussion about their background.

Amika participates in the Obon festival with her peers, engaging in events that touch upon life-and-death themes. She operates almost exclusively within collective activities and group dynamics.