Taeko Nonomiya fulfills the role of school nurse at the narrative's central educational institution, projecting a professional and caring demeanor in her official capacity. Her standard work attire includes a lab coat, frequently paired with glasses. She stands 168 cm tall with body measurements of 94 cm (bust), 66 cm (waist), and 98 cm (hips), and possesses distinctive violet hair reaching chest length alongside green eyes.

Behind this professional facade, Taeko exhibits a manipulative nature. She supplies Mina Hayase with keys to the nurse's office, enabling Mina's intimate encounters with Tomohiro Takabe within that space. Simultaneously, she influences her younger sister Kaori Nonomiya, urging her to pursue Tomohiro more aggressively despite Kaori's existing romantic interest in him.

Taeko personally engages in physical interactions with Tomohiro herself, acting under the assumption that Mina Hayase is unlikely to object. This direct involvement places her at the center of the interpersonal dynamics surrounding the key characters, extending well beyond her professional responsibilities.