Ayumi Shibata is the late mother of Tsugumi Shibata and the former wife of the journalist Hajime Shibata. Her life and untimely death, which occurred prior to the main events of the series, cast a long and tragic shadow over her family, deeply influencing the actions and emotional struggles of both her ex-husband and her daughter.

Ayumi and Hajime Shibata were once deeply in love, and their relationship began as a passionate romance admired by those around them. Her maiden name was Ogawa. However, following the birth of their daughter Tsugumi, Ayumi began to suffer from a growing sense of loneliness. Hajime’s increasing dedication to his work meant he spent less and less time at home, leaving Ayumi feeling emotionally isolated. In her vulnerability and longing for connection, she made the mistake of having an affair. Although she sincerely apologized for this transgression, Hajime was furious and rejected her apology. Plunged into emotional turmoil, Ayumi was involved in a fatal car accident that resulted in her death.

Ayumi is remembered as a loving and sensitive person who struggled under the weight of emotional isolation. Her desire for a meaningful connection ultimately led to her tragic decisions and fate. Despite her flaws, her love for her family remained genuine, and she is an unforgettable presence in their memories. Her life and death left a profound impact, shaping the motivations and actions of Hajime and Tsugumi throughout the series. In the anime, she appears only in flashbacks. In one notable instance, the circumstances surrounding her are used by Ai Enma in an attempt to persuade Tsugumi to send her own father to hell.