Himeko Oogami is an elderly woman who serves as the head of the religious organization founded by the Oogami family. She is the grandmother of Makoto Oogami, one of the main characters.

Himeko holds a position of significant authority as the matriarch of her family’s spiritual tradition. Her primary motivation is to ensure the continuation of her family's religious legacy, and she wishes for her grandson, Makoto, to eventually succeed her as the head of the organization. This goal places her in a position of influence over Makoto, though he does not share her interest in taking on that role.

Physically, Himeko is characterized as a senior with gray eyes and white hair, which is typically styled up in a bun. Her appearance is often complemented by accessories such as earrings, a headband, and lipstick. Her designation as a priestess in some records reflects her central role within the family's religious practices.