Hiroko Hirasawa is an eleventh-grade high school student distinguished by her short green hair styled with blunt bangs and twin tails, paired with violet eyes. Her slim, pale physique stands at 156 cm, with measurements of 81-55-82 cm and a B-cup bust. She favors practical academic attire like lab coats, aprons, school uniforms, skirts, shorts, tank tops, and one-piece swimsuits, often accessorized with glasses, belts, ribbons, or hair ties.

Her kuudere personality manifests as pragmatic, reserved, and detached. A logical loner, she approaches situations analytically, occasionally exhibiting unconventional social behavior. Intelligence and a research-focused mindset define her character.

Orphaned from a young age, Hiroko channels her background into cooking and rigorous academic pursuits. In the original visual novel, she is one of nine romanceable characters, where persistent interaction and dating enable relationship development. The anime adaptation positions her in a supporting role.