Sanae Koshino is the eldest daughter of the Koshino family and a central character in the anime Komekami! Girls. At fourteen years old, she has pink hair cut to neck length and pink eyes, and her appearance is often complemented by glasses and a braid. Her personality is described as naturally dull, setting a calm and perhaps unassuming tone among her more energetic siblings.

As one of the seven Komekami sisters, Sanae is a physical manifestation of a traditional belief that seven deities reside within a single grain of rice. The story begins when their mother, the rice goddess or queen of the rice gods, is suddenly summoned back to the heavenly realm and cannot return to the earthly world. This event forms the core of Sanae's motivation and the series' primary plot. She and her six sisters are left to search for clues about their mother's whereabouts.

In this quest, Sanae and her family use the city of Usa in Oita Prefecture as their home base. A notable ability at their disposal is the power to teleport to Hachiman shrines located throughout the Kyushu region. Her role in the story is not just as a seeker but also as the leader of her siblings, being the eldest. As the narrative progresses, the sisters engage with various local communities to solve problems, during which they learn about food and participate in cooking battles, all contributing to their personal growth. Key relationships naturally center on her six sisters, whose distinct personalities contrast with her own; these include Minori, the cool and independent second daughter; Hikari, the determined fourth daughter; and the timid Mai, one of the younger twins. Sanae's development is intertwined with this journey of discovery, as she and her family learn to work together, tackle regional issues, and mature through their experiences with cooking and local traditions.