Mayu, a cat deity banished from Takama-ga-hara for her severe gambling addiction, lost her divine rank and powers when her mother exiled her. She now resides at Earth's antique shop Yaoyorozudou, owned by human Yuzu Komiya. Their meeting occurred when the spirit of Yuzu’s deceased cat, Kotetsu, guided Mayu to help Yuzu overcome grief, leading to Mayu’s permanent stay.

Diminutive with orange-yellow hair, brown eyes, and prominent cat ears, Mayu’s two tails initially made Yuzu mistake her for a nekomata. Her personality radiates extreme laziness—she sleeps excessively, eats seafood, and plays video games. She displays cat-like behaviors, relishing Yuzu’s homemade pudding and teasing others. Despite her indolence, she genuinely cares for friends and townspeople, especially Yuzu.

Mayu retains one divine ability: using a magical scroll to locate lost items. This aids others, like helping cherry blossom goddess Yoshino recover magical ash essential for seasonal blossoms. Though exiled, her competence surfaces when needed. Her relationships are complex: she is engaged to fellow cat god Sasana Shōsōin through a paternal arrangement. Sasana affectionately calls her "Mayu-sama" and frequently discusses marriage. Concurrently, god Daikokuten’s granddaughter Meiko pursues Mayu, sparking rivalry with Sasana.

Beyond her idle exterior, Mayu intervenes to help Yuzu conquer nightmares about her past, revealing empathy and protectiveness. She assists other deities—retrieving runaway shikigami for onmyoji Yukina Kamo and supporting fox god Gonta against a typhoon deity. These actions underscore her underlying responsibility and loyalty. Her backstory includes familial tensions, particularly with her banishing mother, while her father played a passive role.

Mayu shares Yuzu’s exact birthday, symbolizing their intertwined fates. Her journey balances carefree hedonism with unexpected diligence, illustrating growth through commitment to others despite diminished divinity.