TV-Series
Description
Mei Narusegawa is the younger stepsister of Naru Narusegawa, joining the household when her father married Naru's mother. This family merger was a source of great excitement for Mei, who had always dreamed of having an older sister. However, the new marriage was not well-received by Naru, who viewed the event as her mother replacing her with a new husband and daughter. Following the marriage, Naru eventually left the family home to live at the Hinata House dormitory, a move that left young Mei feeling crushed and abandoned.

Personality-wise, Mei is characterized by a quiet and reserved demeanor. She is a dedicated student who puts significant effort into her studies and is often found reading. A central driving force for Mei is her deep-seated desire to have a happy and unified family. This wish forms the basis for her primary motivation, as she comes to believe that Naru left home because of her presence. Consequently, Mei conceives a plan to transfer to a school overseas in Canada, hoping that if she leaves, Naru will return, and the family can be restored to happiness.

When her parents refuse to allow her to transfer, Mei decides to take action herself and visits the Hinata House. Her goal is to bring Naru home, and she believes the best way to accomplish this is to break up Naru's relationship with the male resident, Keitaro Urashima. She attempts to push Keitaro toward another resident, Mutsumi Otohime, by orchestrating situations that might bring them together. Her most impactful scheme involves revealing an old photograph from their childhood that suggests Mutsumi, not Naru, is the "promise girl" from Keitaro's past that he has been searching for.

Despite her manipulative tactics, Mei is not a malicious character. Her actions stem from a place of emotional need and loneliness. Her plan backfires when a misunderstanding leads to a confrontation where Naru accuses Mei of being selfish. Hurt by her sister's anger, Mei breaks down, only to be comforted by Keitaro, who reassures her of Naru's true affection. This moment marks the beginning of Mei's development. She realizes how important Keitaro is to Naru, despite her sister's denials, and shifts from being an antagonist to a supportive figure.

Following this turning point, Mei continues to support her sister from the sidelines. She visits the Hinata House occasionally, cheers for Naru from the top floor of Tokyo University during exam results, and assists Naru in reuniting with Keitaro. Her role in the story is therefore that of a catalyst, whose initial conflict ultimately serves to strengthen the bond between the main characters. In terms of abilities, Mei is portrayed as academically diligent and intelligent, a trait she shares with her sister. While her presence is significant in the anime adaptation, Mei only makes brief, non-speaking cameo appearances in the original manga's epilogue.