Maho is the older sister of Nitori Shuuichi, in fact, Shuichi as a girl looks almost identical to the older sister. She is one year older than Shuichi is, and at the beginning of Wandering Son, she is in the sixth grade of elementary school. Maho shows a strong interest in clothes, and spends much of her money on new apparel. So it is no surprise that she earns her money by modeling teen clothing fashions. Her personality is seen as the opposite to Shuichi's calm and quiet demeanor, often being loud and outspoken. She also sees Shuichi's perceived " cross-dressing " supposedly as a mental sickness, and that it isn't something that a " normal " Shuichi should be doing, thinking and tolerating it because that supposedly is only a phase. She acts out of concern for Shuichi, even if it isn't shown outwardly.
She is a big fan of a teen fashion model named Maiko, and to meet her, Maho auditions for the same modeling agency as Maiko. After she is hired and becomes recognized as a teen model, Maho enjoys being asked for her autograph by complete strangers. While her modeling career initially starts out slowly, Maho soon gains confidence in her abilities, and becomes friends with Maiko and two other fashion models, Anna Suehiro and Tamaki Satō. In contrast to her younger sibling, Maho is very out-spoken and tends to be rough with Shuichi, even hitting or slapping Shuichi on occasion, and she often forces things on Shuichi with little consideration of Shuichi's opinion. She does not like Shuichi's supposed " cross-dressing ", and does not understand that Shuichi is dressing as a girl because of their female gender identity. She gets angry and disturbed when she finds Shuichi one time dressed as a girl, in Maho's own teen fashion outfit of a cardigan, blouse, and mini-skirt, when she returns to the bedroom to retrieve her cell phone. In junior high school, Maho becomes attracted to her classmate Riku Seya, and eventually starts dating him.
She is shown throughout the series, usually as a counter towards Shuichi's attempts to present as their correct gender of a teenage female, as being very vocal against one doing so, as she perceives it as weird, and something that supposedly hinders Shuichi's social future. Although seemingly harsh towards Shuichi, she is known to care deeply for him. One time, she, at first, had compared herself as to looking like Shuichi, but Riku corrects her, saying that Shuichi looks like her, not the other way around.
Later, Maho helps Shuichi get closer to Anna Suehiro, and when Shuichi starts dating Anna, she tries to make sure that Shuichi won't dress as a girl again, as she feels that Anna is 'normal' and what Shuichi does is weird. But the opposite actually happens when Anna asks Shuichi out on a girl's 'shoujo ai' ( girl's love ) date, with both of them dressed as cute, teenage girls. Anna assumes that Maho would not want to be her close friend, but this is shown to be untrue, and they eventually get along fine after Shuichi and Anna get back together.