Imari Kurumi, commonly called Imari, grew up next door to Minase as his childhood friend since kindergarten. They attended the same academy as seniors and joined the art club, where Imari rose to become president. Minase's parents entrusted her with his care during their absences, leading her to wake him daily, sometimes employing physical methods learned from her Shorinji Kempo training, in which she held a black belt and won a national tournament. She occasionally cooked meals for him, demonstrating culinary skill, while secretly harboring romantic feelings.

Physically, Imari possessed large turquoise eyes and long brown hair, typically styled in a ponytail secured by a distinctive orange pearl-shaped hair tie she retained into adulthood. As a student, she wore the academy uniform. Casually, she favored a blue jacket over a black top with a diagonal stripe, a white skirt with a brown belt, and blue-and-white striped knee-high stockings. As an adult, she briefly served as a police officer before joining the paranormal investigation agency Tokken, adopting their uniform. Off-duty, she wore a shiny orange jacket, a light blue skirt, and high black stockings. While possessed by Reika Kitami, she wore red robes or a revealing red dress.

In her youth, Imari was shy, kindhearted, yet temperamental, especially when Minase teased her, often reacting with physical outbursts. She was punctual and dedicated to the art club, but sensitive to emotional turmoil, such as witnessing Minase's involvement with other girls. After encountering Kitami, her demeanor became cool and reserved, though she remained supportive of colleagues like Aki Ichikawa at Tokken. Her sexual orientation appeared heterosexual, with interests sometimes influenced by external factors like aphrodisiacs; she willingly engaged in acts with Minase after their mutual confession of feelings.

Her story began upon witnessing Minase's initial use of black magic, causing unsettling school events. Discovering Minase with student council president Rika Shiraki led her to avoid school, heartbroken. Defying Minase's warning, she visited the art club and found Kitami's followers assaulting Shiraki and faculty advisor Hiroko Takashiro. Kitami targeted Imari as a virgin sacrifice for a body-exchange ritual. Imari was drugged with aphrodisiacs, fitted with a chastity belt, and subjected to sexual acts by Kitami's lackeys, including Minase under magical influence. During the Walpurgis Night ritual in the school basement, Kitami's soul partially possessed Imari's body; Takashiro later sealed Kitami's presence, causing Imari to forget the events.

In her final school year, a male classmate assaulted Imari, raping her in a storage room after initial resistance; she eventually submitted. Kaori Saeki also lured her back to the basement, performing a ritual that reinforced Kitami's essence within her. Post-graduation, Imari joined the police. Exposure to Kitami granted her latent psychic abilities, enabling her to identify criminals during investigations. This attracted Toru Yuge, who recruited her into Tokken. As a chief investigator, she handled paranormal cases, including murders linked to magical activity at her former academy. During a bank hostage situation with colleague Aki Ichikawa, a robber's incantation reactivated Kitami's soul, breaking Takashiro's seal. The dominant Kitami used Imari's body to retrieve the Spear of Longinus and infiltrated Tokken to advance her agenda.

Minase rescued her from Kitami's initial ritual after breaking magical control, leading to their mutual confession and consensual relationship. His later disappearance implied potential offscreen elimination by Kitami.

Traumatic events, including multiple sexual assaults, forced drugging, and psychological manipulation during possession, marked her development from an innocent youth to a hardened investigator. Traces of her original kindness persisted in professional interactions. Her unresolved connection to Kitami remained a defining aspect of her existence into adulthood.