Baby Koume Jinguji originates as a wealthy, stern elderly woman who lived in isolation on her privately owned remote island. Her harsh demeanor reflected a lifetime of authority and independence. After her death, her daughter gives birth to a baby girl, Amika's younger sister. This infant possesses a striking physical resemblance to the deceased grandmother, sharing identical facial features and expressions. Crucially, the baby's behavior and personality traits mirror the grandmother's precisely, including her stern disposition and characteristic mannerisms.

This reincarnation-like phenomenon directly shapes Amika's life trajectory, introducing complex familial dynamics. The baby's presence and grandmother-like behavior act as a catalyst for shifts in Amika's perspective and priorities, particularly concerning her aspirations and family relationships. The baby fully embodies the grandmother's essence, functioning as a continuation of her identity within the family structure.