Miki appears as a friend of Kayo Asakura. She witnesses Kayo suddenly give birth to an infant demon beast at home. The newborn immediately assaults Miki, impregnating her and twisting her into an alien minion under the demon beast's control.

This transformation reshapes her body and mind, binding her to the demon beast's goals. In her mutated state, she participates in subsequent events, including an attack at a hospital. There, an Interplanetary Mutual Observation Agency operative intervenes with a physical maneuver that forces Miki back into her original human form temporarily.

However, her link to the demonic forces endures. Later events depict her possessed or influenced once more by these entities, showing a recurring susceptibility to their control.

In the sequel series *Demon Beast Resurrection*, Miki returns as a chosen vessel. A sukeban selects her body specifically for the resurrection of Ash, a deceased member of the Interplanetary Mutual Observation Agency task force. This role underscores her continued exploitation and significance within the conflict between the demon beasts and the agency.