Rika Akagawa attends high school as a classmate of protagonist Kenta Kogure. She possesses pink hair styled with spiky bangs and twin braids, brown eyes, a slim and petite build, and pale skin, resulting in a strikingly youthful appearance often mistaken for an elementary school student. Her standard school uniform includes glasses and is accessorized with ribbon hair ties and a string ribbon tie.

Personality-wise, Rika exhibits a reserved nature and a deredere demeanor, revealing moments of sweetly flustered affection regarding her feelings. Her fundamentally innocent outlook and behavior contribute to perceptions of naivety or immaturity. She harbors a secret romantic interest in Kenta Kogure, but her deeply timid and cowardly nature prevents her from confessing, defining her inhibited interactions.

Within the narrative, Rika becomes involuntarily trapped inside an abandoned school building alongside Kenta and other classmates following a deceptive letter. Her confined existence persistently revolves around her unspoken affection for the oblivious Kenta. This emotional subplot becomes marginalized amidst group dynamics, particularly Kenta's preoccupation with classmate Kotomi Asakawa and Munemitsu Soga's aggressive jealousy toward Kenta. While the group navigates escape and internal conflicts, Rika's personal arc remains focused solely on this unresolved romantic tension.