Eri Totani works as a career-driven planner in the corporate world. She has cohabited with Shigeyuki Honda, an illustrator known as Peter, for two years following their meeting on a Hawaiian vacation. Eri prioritizes her professional ambitions, actively pursuing advancement within her company and demonstrating a strong dedication to climbing the corporate ladder. This career focus is central to her character and drives her rejection of traditional relationship milestones like marriage and raising children.

Her opposition to starting a family creates significant tension with her partner, who strongly desires marriage and children. This fundamental difference in life goals steadily erodes their domestic harmony, leading to emotional distance and recurring arguments between them. The conflict intensifies over time, contributing to Eri's eventual decision to temporarily leave their shared home to reassess the relationship and her own feelings. This departure serves as a pivotal point in the narrative.

While the core narrative presents Eri's resistance to family life as stemming from career priorities, later developments suggest this stance may originate from unresolved personal trauma. The exact nature of this trauma remains unspecified, but it is framed as a formative influence on her life choices and relational dynamics. Eri possesses dark hair, though specific details beyond this are not elaborated. Her surname is Totani.