Miyuki, cousin to Kayō Asakura, trains as a miko at Ōyama. Her inherent spiritual nature leaves her susceptible to supernatural forces, resulting in her possession by the Hybrid—the offspring of Kayō and the Vanguard. This possession irrevocably changes her role in the conflict.

Following this, Miyuki founds and commands a cult focused on resurrecting the Hybrid. Her devoted followers, including figures known as "The Mailman" and "The Slave," operate under her directive to achieve this resurrection. Their strategy involves capturing Kayō to enact an erotic sacrifice intended to summon the Hybrid back from death.

Miyuki wields the supernatural "Black Card." This artifact transforms upon contact with blood, especially Kayō's, manifesting the monstrous entity Utsushiro to carry out Miyuki's will.

Her efforts culminate in a ritual exploiting Kayō's connection to the Hybrid to facilitate its return to Earth. During this event, Miyuki undergoes a physical transformation. Her body becomes the vessel for the resurrected Hybrid, merging her existence with the entity she sought to revive. This transformation marks her final evolution from a possessed victim into an active conduit for the invasion forces.