Madoka Tanesato is Mizuto Irido's second cousin and the older sister of Chikuma Tanesato. She possesses long brown hair, purple eyes, and wears sharp red square-rimmed glasses. Her sociable and approachable personality marks her as a positive individual who easily builds rapport with new acquaintances.

Madoka appears when Mizuto and Yume Irido visit their father's family home. Interacting with Yume, she discerns Yume's lingering feelings for Mizuto and offers support regarding their romantic difficulties. Later, during a school festival, Madoka facilitates Mizuto and Yume's participation by lending them costumes for a university cosplay café.

A significant age gap exists between Madoka and her younger brother Chikuma; she attends university while he is an elementary school student. This creates a sibling dynamic defined by Madoka's outgoing cheerfulness against Chikuma's introverted quietness. Madoka maintains a purely familial relationship with Mizuto, with no romantic history despite Yume's initial suspicions.

Her name carries symbolic meanings: "Madoka" combines the characters for "circle/money" (円) and "fragrance" (香), while "Tanesato" incorporates "seed/variety" (種) and "village" (里). Her actions primarily focus on creating opportunities for Mizuto and Yume to interact, actively facilitating their evolving relationship.