Hatsuho Kazami is a major supporting character in the anime, introduced as the mother of the protagonist Mizuho Kazami. She is a widow who lost her husband when Mizuho was young, and she is also the mother of a younger daughter named Maho Kazami. Hatsuho is an alien, like her daughter, though she possesses a very youthful appearance that often belies her status as a parent.

In terms of personality, Hatsuho is highly self-assured, bold, and possesses a subtly assertive demeanor. She is portrayed as one of the more mysterious and unpredictable characters, with a strong sensual and playful side. She delights in teasing her eldest daughter and son-in-law, often demanding to know intimate details about their relationship and concocting schemes to "spice up" their love life. These schemes can be quite elaborate, such as playfully kidnapping Kei and taking him to an adult hotel. Despite her flirtatious and sometimes chaotic behavior, there is an underlying layer of care and responsibility, as her primary motivation appears to be ensuring the happiness and passion in her daughter's marriage.

Hatsuho's role in the story is largely that of a comedic catalyst. She does not have a daily role at the school but appears specifically to interact with her family. Her most significant actions take place in the later parts of the series, particularly in the thirteenth episode, where she visits Mizuho and Kei. Her main goal is to push the shy, newlywed couple into becoming more intimate with each other. To achieve this, she orchestrates situations that force Mizuho and Kei together, removing their inhibitions through playful manipulation and mock-bondage scenarios. While she is sexually forward and implies an attraction to Kei because he resembles her late husband, her actions are ultimately designed to benefit the couple rather than for her own gratification.

Her key relationships center on her family. She is the mother of Mizuho and Maho, and the mother-in-law to the main male character, Kei Kusanagi. Her dynamic with Mizuho is one of a mother who is not above embarrassing her daughter for what she sees as the daughter's own good. With Kei, she is teasing and physically forward, viewing him fondly as a son-in-law who fits her preferred type. The character does not undergo significant personal development throughout the series; rather, her function is to instigate change and development in the primary relationship between Mizuho and Kei.

Hatsuho possesses a few notable abilities, though they are not combat-oriented. Like her daughter, she is an alien with access to advanced technology, which includes teleportation devices that she uses for dramatic and comedic effect, such as teleporting Kei away from his friends. Her most notable skill, however, is her talent for psychological manipulation and matchmaking, using her bold personality and schemes to break down the social barriers and shyness of the main couple.