Maho is the younger half-sister of the brilliant but troubled guitarist Ryusuke Minami. She shares her brother's background, having lived in the United States for a significant period. This upbringing makes her more fluent and comfortable with English than Japanese, and she sometimes struggles with reading kanji characters. She is of average stature with large, expressive eyes and long, shiny black hair, which she often wears down with spindly bangs or in a ponytail. Her appearance is striking enough that she works as an amateur model and aspires to become a successful actress.

On the surface, Maho projects a tough, confident, and sometimes brash personality. She is outgoing, cheerful, and not afraid to speak her mind or act in a coquettish manner. However, this exterior often masks a more fragile and insecure interior. She can be surprisingly sensitive and easily hurt, revealing a vulnerability that contrasts with her confident front. This duality is central to her character; she is a passionate individual who feels things deeply, even as she tries to appear unshakable. For instance, despite being a gifted vocalist, she lacks confidence in her own singing ability and needs encouragement from others to recognize her talent.

Maho serves as a critical source of motivation and emotional support for the protagonist, Yukio "Koyuki" Tanaka. She is one of the first people to recognize Koyuki's latent musical talent, even suggesting he become the vocalist for the band that would become BECK. Her faith in him is a powerful force that helps him push through his self-doubt and insecurities as a performer. The development of her relationship with Koyuki forms a primary romantic arc of the story. Their connection begins somewhat tentatively, with Koyuki unsure if her friendly and flirtatious behavior indicates deeper feelings. This evolves gradually and complexly; she maintains a degree of emotional distance at times while making her interest undeniably clear at others, such as when she insists on sleeping over at his house. The two eventually begin a romantic relationship.

Her relationship with her brother, Ryusuke, is equally significant and forms a touch-and-go dynamic. They have a complex sibling bond where they can get along fine one moment and fiercely fight or refuse to speak to each other the next. Despite this volatility, Ryusuke acts as a protective older brother figure. He is aware of her feelings for Koyuki and actively looks out for her, even trying to help nurture their relationship. Maho's world is largely defined by these two central figures: her brother, who is consumed by his musical ambition, and Koyuki, who is drawn into that world. Through her interactions with them, she navigates her own path, dealing with the music scene, her personal ambitions, and the complexities of young love.

Maho is a talented singer and often performs on stage at clubs. Her ability as a vocalist is highly regarded, even if she personally doubts it. Beyond singing and modeling, she harbors a strong desire to work behind the camera, expressing an interest in becoming a filmmaker. Her bilingual ability, a direct result of her time in America, is a notable asset that distinguishes her from many of the other Japanese characters in the story. This combination of artistic sensitivity, outward strength, and inner vulnerability makes her a catalyst for much of the story's emotional development, particularly for Koyuki.