Madoka Kōmoto, the only daughter of the priest at Yamabiko Town's local Shinto shrine, serves as a miko outside school hours. She sweeps leaves from the shrine's sandō and reads books to children at the Yamabiko library. Her duties include performing as the divine dancer for the shrine's New Year's Eve rite.

She possesses indigo-blue irises and long, straight indigo-blue hair reaching her crotch, typically tied with a narrow white belt. Though younger than Kazuma Hoshino, she is slender and well-endowed. Her attire features the traditional miko costume, a white longuette with a straw hat during outings, and school uniforms.

Madoka first met Kazuma Hoshino eight years prior during his visit to Yamabiko Town with his father. They became friends during his brief stay, and he gave her a "love successful" talisman, which she interpreted as a marriage promise. When Kazuma returns years later, he initially fails to recognize her. Their reunion shocks Madoka, triggering her heterophobia and causing her to flee. Subsequent encounters at school and the shrine lead to mutual apologies, and they begin addressing each other by first names. Their relationship deepens, with Kazuma drawn to her appearance and personality while Madoka harbors persistent feelings for him.

During a "summer carnival," other characters deliberately leave Madoka and Kazuma alone to facilitate a confession. Madoka becomes angered after accidental events remind her Kazuma forgot their childhood promise, causing a temporary setback. Kazuma eventually recalls their past: he befriended the then-solitary Madoka and gave her the talisman as a token for their reunion. After apologizing and asking to become her boyfriend, Madoka happily accepts, and they begin dating.

As New Year approaches, Madoka practices her mikomai. Kazuma must take his brother back to the city for medical attention but promises to return before her performance. Heavy snowfall delays his train, leaving Madoka heartbroken and unable to focus. Kazuma eventually arrives after risking a journey through dark, snowy mountains. Encouraged by his presence, Madoka restarts and completes the dance perfectly, earning applause. Their relationship gains public acknowledgment. The visual novel concludes with Kazuma and Madoka sharing a deep kiss under a starry sky in spring, swearing eternal love. Her afterstory in the fandisk, set one year after Kazuma's arrival, confirms they maintain a happy romantic relationship.

In the anime adaptation, Madoka similarly befriends the young Kazuma, receiving a grass ring as a keepsake. Upon their reunion years later, Kazuma has forgotten her. Though he eventually recalls their past during a riverbank date, he has already fallen in love with Ui Nakatsugawa. Madoka peacefully ends their relationship, standing alone by the river as she releases the grass ring into the water, bidding farewell to her first love.

The manga adaptation largely follows the visual novel's storyline, depicting Madoka and Kazuma becoming a couple and sharing a kiss under the night sky.

Madoka lives with her parents at the shrine, her grandparents having passed away earlier. She befriends Hina Sakai, who transports water from the Komoto shrine to her family's liquor store and encourages Madoka to confront her feelings for Kazuma. During summer vacation, she befriends Minato Nagase while serving as a tour guide.

Madoka enjoys writing, is skilled at nage-waza, and has a particular fondness for honey. Her relationship with Kazuma spans nearly a decade, making it the longest depicted in the series.