Ai Kagano is a magical warrior dispatched from another world to eliminate Yuragi demons in Tokyo. These demons feed on human negative emotions and commit brutal acts. Operating undercover, she poses as a high school student to track them discreetly. Her mission is compromised when classmate Akitoshi Okajima follows her, witnessing her confront a Yuragi and exposing her true identity.

She has blue shoulder-length hair, red eyes, and wears a distinctive magical girl costume: a blue skirt suit with short sleeves, a black leotard, purple thigh-high boots, and a red ribbon hair tie. In her civilian disguise, she wears a standard school uniform.

Her personality is intensely focused on her mission, preferring to work alone with a strong-willed, self-sufficient demeanor. She actively discourages others from interfering. Despite this solitary approach, she risks her cover to protect civilians, such as when Akitoshi or his friends are targeted by Yuragi.

She wields a Magic Lance as her primary weapon. Her Magi physiology grants superhuman strength, speed, and sensitivity to mana. Her combat techniques include "Thunder Blast" and "White Dragon Purification Method." Under extreme duress, she can enter a berserk mode.

In later storylines, she operates alongside fellow magical warriors Rin and Megu. Rin is identified as her sister. They confront collaborative Yuragi attacks together. Rin's personal history, involving giving birth to a daughter named Mayu after a rape, becomes intertwined with their collective battle.

Her development reveals a shift from strict isolation to reluctant collaboration. While initially dismissing connections, her repeated interventions to protect Akitoshi and his friends demonstrate a latent sense of duty beyond her mission. Her participation in joint operations with other warriors in the sequel series indicates an adaptation to larger threats requiring teamwork.