Ai Kunugi is a middle school student whose life was irrevocably altered by the deaths of her older sister and infant niece. Her sister took her own life after being falsely blamed for the accidental death of her baby daughter. Ai suspected the infant's true killer was her sister's boyfriend, Kago, a yakuza boss, but lacked proof. She sought help from Misaki Saiki, triggering an investigation that exposed the truth: Kago murdered the infant, and Ai's sister succumbed to despair.

During this trauma, Ai discovered a shared ability with Misaki to perceive and communicate with spirits, revealing her latent necromantic powers. As a novice necromancer encountering spirits regularly, she viewed Misaki as a mentor, aspiring to develop similar strength and skill. Despite Misaki's warnings about the dangers, Ai confronted supernatural phenomena with notable courage. This bravery extended to physical peril, including escaping an attempted assault by Kago when she returned alone to her sister's apartment seeking evidence.

Ai's traumatic journey included witnessing a failed mass-suicide ritual orchestrated by Yuo, where classmate Mitsuru Fujiwara saved her. This event inflicted deep psychological trauma, yet Ai persisted in her necromantic work. Following the ritual's catastrophic outcome and Misaki's subsequent emotional withdrawal, Ai found herself compelled to take on greater responsibilities within the Livelihood Preservation Group, marking her growth into a more independent and capable necromancer despite ongoing challenges.