Hinano Hiiragi is the eldest sister of the Hiiragi family, possessing a strikingly youthful appearance that contrasts with her senior position. She stands at 148cm tall with a slim physique and pale skin. Her white hair is cut in a short bob featuring spiky bangs and an ahoge, paired with violet tsurime-shaped eyes.

A prolonged childhood illness impaired her physical development, permanently cementing her childlike stature. Though recovered, she maintains a chronically weak constitution. This history fuels a deep-seated inferiority complex about her perceived lack of maturity and authority. Outsiders frequently mistake her for the youngest sibling, exacerbating her emotional struggles.

To compensate for her youthful look, Hinano adopts a strict, traditional demeanor, striving to embody the Yamato Nadeshiko ideal. She exhibits a protective nature towards her family and maintains a formal, disciplined approach as family leader. Her commitment to tradition is evident in her typical attire of kimonos, miko dresses, and robes, often accessorized with a hand fan.

Distinct behavioral traits include presenting candy to her sisters alongside verbal praise, a habit the family accepts without comment. She owns a supernatural three-tailed fox-like pet capable of levitation that constantly accompanies her.

All siblings in the Hiiragi household are adopted. As the eldest, Hinano interacts with her sisters and sole brother, Kuya, blending authority with nurturing concern. Her efforts to uphold her responsibilities despite her childlike appearance form a core aspect of her character development.