Mone served as a shrine maiden alongside her older twin sister, Ane. Their family guarded the Koryuumon, Earth's largest Dragon Hole regulating the planet's energy flow, a duty that included protecting sacred dog deities like Sadaharu and Komako. The Amanto's construction of the Terminal atop the Koryuumon destroyed their shrine. Jobless and displaced, Mone adopted a reclusive lifestyle, refusing alternative work while insisting she remained a shrine maiden. She expresses strong disapproval of Ane working as a hostess to support them, viewing it as a betrayal of their spiritual heritage and fueling frequent arguments. Standing 169 cm tall, Mone has black hair with blunt bangs reaching her chest. She consistently wears traditional priestess attire: a white haori, red hakama, and a necklace with a single magatama. Her personality combines bluntness and laziness; she avoids responsibilities, spends her days at home, describes herself as a shut-in, and rejects conventional work. Yet, she demonstrates deep care and guilt toward the animals she once protected, particularly Sadaharu, whom she reluctantly abandoned. Mone first appears in the Inugami Arc, responding to news of Sadaharu's uncontrolled growth. She and Ane rush to help the Yorozuya revert him. During the ritual, Mone's clumsiness causes her significant injury, but they succeed by trapping Sadaharu in a pentagram of thrown baseballs. Her regret over abandoning Sadaharu surfaces, and she feels profound gratitude toward the Yorozuya for treating him as family. Her background expanded in the Silver Soul Arc, showing the Tendoushu orchestrated their shrine's destruction to seize control of the Altana Gate, a vital planetary energy structure, underscoring her lingering spiritual responsibilities. Mone retains strong spiritual abilities tied to her heritage, including ritual expertise and managing sacred dog deities. Her knowledge remains intact, enabling decisive action when necessary. She maintains a close bond with Komako, the remaining sacred dog under her care, whom she treats affectionately. Her relationship with Ane stays strained due to their divergent coping strategies, yet underlying familial loyalty persists. In the spin-off "3-Z Class Ginpachi-sensei," Mone appears in light novel illustrations and anime adaptations. She communicates primarily through a recorder, producing sounds understood only by Ginpachi-sensei, adding a whimsical layer in non-canonical settings.