Haruka's Mother is a minor character whose role in Ultra Nyan: Hoshizora Kara Maiorita Fushigi Neko is defined primarily by her relationship to the protagonist, Haruka. Identified in the cast only by this familial connection, she appears as a parental figure whose actions are rooted in the practical realities of daily family life rather than the extraordinary events unfolding around her daughter. Her primary narrative function stems from a key household rule: her family lives in a residence where keeping pets is not permitted. This restriction becomes a significant point of domestic conflict, as it directly opposes Haruka's desire to care for the injured cat she discovers, whom she names Myau (later revealed to be the alien Ultra Nyan). When Haruka's mother discovers cat food hidden in her daughter's desk drawer while cleaning her room, she scolds Haruka for breaking the house rules. This act of discipline, while presented as a standard parental response to a rule being broken, inadvertently sets off a chain of emotional events. The scolding is overheard by the hidden cat, who consequently removes the bandage from his healed paw and leaves the house, venturing out into the rain.

This character does not possess any notable abilities or partake in the science fiction elements of the plot, such as Ultra Nyan's transformations or the conflict with cat kidnappers. Her motivations are grounded in maintaining order and adhering to the practical restrictions of their home. There is no documented evidence of her developing a deeper understanding of the alien cat's true nature or undergoing a significant character arc. Her relationship with Haruka is the sole relationship detailed in the narrative, and she remains a static character who serves as an obstacle to the protagonist's wish to keep a pet, thereby contributing to the story's initial conflict. The resolution of this conflict occurs externally, as Myau ultimately remains with another character, Yuki, rather than returning to Haruka's home.