Koto designates two interconnected characters bound by family and creation. The first, Lady Koto, began as a black rabbit drawn by the priest Myoe. A Bodhisattva granted her human form through a pact, enabling her to confess love to Myoe. They married and raised three children: Yakushimaru, an adopted war orphan, and Yase and Kurama—beings Myoe drew to life. The family dwelled in Mirror Kyoto, a surreal city crafted by Myoe, until Lady Koto’s obligation to the Bodhisattva compelled her departure. Transferring her powers to her daughter weakened her, trapping her on a desolate moon as she could no longer sustain her presence across dimensions. Her eventual return jeopardizes the multiverse’s stability.

The second Koto is the 14-year-old daughter of Lady Koto and Myoe (later called Inari). Born after her parents left Mirror Kyoto, she inherited her mother’s powers, causing Lady Koto’s decline. Raised solely by Inari within the Shrine organization, she received combat training and inherited familiars A and Un, embodying "the beginning" and "the end." She wields the dimension-piercing hammer Aratama, with garnet-red eyes marking her lineage. Feeling abandoned after Inari vanished, she pursued a black rabbit into Mirror Kyoto with A and Un, seeking family clues and a way home. Viewed as a disruptive outsider, she challenges the stagnant rule of her half-siblings—Yakushimaru (now Myoe), Yase, and Kurama. Her journey involves reconciling her identity, recognizing Inari as her father, and understanding her mother’s sacrifice. Her actions inadvertently enable Lady Koto’s return and attract the multiverse-maintaining Shrine’s attention. Ultimately, she resolves the conflict between her family and the Shrine, reuniting her fractured family and embracing her role.