TV-Series
Description
Kasumi is a beast-race individual characterized by long purple hair, purple-pink eyes, and distinctive Doberman ears. Her hair is typically pinned back behind her right ear with a clip, featuring two strands framing her face. She wields a cane topped with a question mark-shaped crystal as her primary weapon.

In her Magical Girl identity, Misty★Kasumi, her appearance shifts to lighter purple twintails decorated with ribbon bows and spade symbols. Her outfit comprises a purple and white beret, a translucent white mantle, a short purple dress, and knee-high boots. The cane transforms, gaining a pink heart-tipped crystal, white wings, and a ribbon bow. Attending Tsubakigaoka Private High School in her real-world persona, she lacks beast-race features but retains similar facial traits, wearing the school uniform: a red-patterned ribbon bow, white shirt, pink jacket, black thigh-high socks, and a red skirt.

Personality-wise, Kasumi projects confidence as a detective, proud of her deductive abilities. She openly acknowledges an inferiority complex, which triggers anxiety and loss of confidence when comparing herself to others, particularly in her real-world life where she struggles with simple deductions and exhibits social isolation. Despite this, she demonstrates kindness and empathy, notably supporting her shadow mimic Kiiri and motivating her.

Her background in Astrum involves leading investigations into the world's Shadows. She recruits Yuuki as her assistant, and together they capture a Shadow mimicking Kasumi. She names this mimic "Kiiri" to avoid dehumanizing labels. Their research progresses, but Kiiri begins fading. Yuuki uses his powers to prolong Kiiri's existence, leading to a shared dream set in "That World," where Kiiri manifests as a communicative gray cat. Kiiri ultimately vanishes, leaving Kasumi mourning, though archived data suggests potential future dream encounters.

As Misty★Kasumi, she initially sealed her powers after arresting a thief who mocked her "Magical Detective" identity, feeling overreliance on magic conflicted with her detective aspirations. She reactivates her abilities to protect Yuuki from a ring-enhanced delinquent. This sparks a case involving magic rings, culminating in a cave confrontation where she destroys the rings' source material. Through this experience, she reconciles her dual identities, declaring she will remain both a detective and a Magical Girl. Later, during an amusement park outing with Yuuki, she overcomes initial self-doubt to improvise as a replacement Magical Girl actor, solidifying her acceptance of the role.

Her relationship with Yuuki begins professionally when he answers her detective-assistant job posting. Their dynamic evolves into a close partnership during Shadow investigations, with Kasumi playfully expressing jealousy over Kiiri's bond with him. In "That World," she is his underclassman and only close friend, referring to him as "senpai." A shared memory there involves them solving a flowerbed mystery, identifying a cat named Kiiri as the culprit, reinforcing thematic parallels between realities.