Yūna Konnyaku is a central figure whose history is deeply entwined with that of the Kagemori family, a clan that has secretly served as her protectors for 400 years. Mamoru Kagemori continues this legacy, having watched over her since their kindergarten days.

She is notably clumsy and often ditzy, a disposition that routinely leads her into troublesome and dangerous situations. This tendency requires the constant vigilance and intervention of her guardian, Mamoru.

Her light pink hair is styled with two front braids tied with yellow ribbons, while the rest falls freely. She has large brown eyes and is typically seen in her school uniform, which she accessorizes with black thigh-high socks.

Despite her airheaded nature, she possesses a deep emotional capacity. She cherishes a photograph of herself with Mamoru, looking at it every night before bed, an action that hints at a profound, though unspoken, romantic affection for him. This love surfaces in moments of jealousy, such as when she prevented other girls from holding his hand during a zoo trip.

Her lack of awareness and self-preservation often positions her as someone who requires protection to survive, a role Mamoru fulfills. She once briefly pursued a promising idol career but abandoned it because it would have separated her from Mamoru, demonstrating her prioritization of their relationship over fame.

Her character development culminates in a significant emotional moment where she confesses her love to Mamoru. This development is later undone by a laser-guided amnesia event that erases her memory of both the confession and the revelation of Mamoru's secret identity as her ninja protector.