Harumi Kimihara, a minor character, comes from a family facing financial hardship. Her father, a company president, secured a substantial loan from a finance company run by Genzou Nanahara, the father of fellow Seio Girls' Academy student Kaoruko Nanahara. This debt creates underlying tension and distress for Harumi's family.

Harumi holds resentment towards Kaoruko, not due to personal grievances against her, but because of the wider consequences stemming from their families' financial arrangement. She frequently directs this resentment at Kaoruko through subtle, pointed remarks during their interactions. Privately, however, Harumi acknowledges Kaoruko's inherent sincerity and upright character. This recognition complicates her feelings and makes sustaining her hostile stance increasingly difficult over time.

The tension between them reflects an unresolved conflict, though Harumi's growing awareness of Kaoruko's genuine nature suggests an internal shift, even without overt reconciliation. Her character arc highlights the struggle between ingrained resentment and the emerging acknowledgment of Kaoruko's integrity.

Harumi is a high school student at Seio Girls' Academy and is involved as a violinist, though specific details about her musical activities or other personal attributes are not elaborated.