Kotomi Irie is the young daughter of Naoki Irie and Kotoko Aihara, born years after their marriage and appearing near the conclusion of the narrative. She is introduced as a small child, around four years old, and serves as a symbol of the life the central couple builds together. Her appearance reflects her parentage: she has brown hair often styled in pigtails with pink polka dot bows, and light brown eyes inherited from Kotoko.

Her personality is markedly energetic and mischievous. Kotomi enjoys stirring up trouble at home and displays a lively, sometimes disruptive temperament. She openly admires her father and frequently competes with her mother for Naoki’s affection, leading to comical clashes. Naoki tends to favor Kotomi in these moments, which frustrates Kotoko yet also highlights the playful family dynamic. Despite the teasing and rivalry, Kotomi genuinely loves Kotoko and remains deeply attached to both parents.

Within the story, Kotomi’s role is largely that of a supporting character whose presence reinforces the happy outcome of the main romantic arc. She appears toward the very end of the series, adding humor and heartwarming domestic scenes that illustrate the family the former high school sweethearts have created. Her appearance provides a sense of closure and continuity for the Irie household.

Due to her young age and limited screen time, Kotomi does not undergo extensive personal development over the course of the series. She functions as a charming result of the lead characters’ growth rather than a figure with her own evolving arc. Her key relationships are with her parents, where she both adores and playfully challenges Kotoko and strives for Naoki’s attention. Her energy and inclination to cause lighthearted trouble echo traces of Kotoko’s own spirited nature, making her a fitting addition to the family.