Natsuki is an 11-year-old girl who feels deeply alienated from her human peers, adopting the belief that she is a magician from Planet Popinpobopia. She views conventional human society as a "Baby Factory" designed solely for procreation, a system that subjects her to constant scrutiny and abuse. Highly imaginative, she endures her difficult home life by relying on a system of self-created magical powers and the guidance of her stuffed hedgehog, Piyyut. As an adult, she enters an asexual marriage of convenience to evade societal expectations.

Yuu is Natsuki's cousin, older by two years, who similarly feels like an outsider within his own life. He validates Natsuki's magical worldview by claiming that his mother told him he is an alien waiting for a spaceship to take him home. He struggles deeply between his authentic sense of self and the intense pressure to assimilate into regular human society, frequently trying to obey the unspoken orders of the adults around him.

Tomoya is Natsuki's 34-year-old husband, whom she meets through a website dedicated to unconventional, asexual marriages. Also a survivor of childhood familial abuse, he acts as an intellectual ally to Natsuki by coining the term "the Factory" to describe the reproductive pressures of society. He approaches social taboos with a clinical, detached logic, actively seeking to deprogram himself from human conditioning.

Kise is Natsuki's older sister and the favored child of their mother. Having experienced cruel teasing in her youth for her appearance, she responds by fiercely clinging to conventional expectations and becoming an active enforcer of normal behavior. She frequently projects her anxieties onto her younger sister, acting as an antagonist within the household.

The rigid matriarch of Natsuki's immediate family. She prioritizes societal appearances above her children's safety, frequently dismissing Natsuki as a disgrace while lavishing praise on Kise for fitting in. Her severe physical and emotional reactions to Natsuki's problems reinforce the strict behavioral codes of their suburban town.

A handsome and outwardly respectable instructor at Natsuki's cram school. He uses his position of authority and charm to groom and exploit vulnerable students. His predatory behavior represents the hidden dangers that exist perfectly undetected within the rigid, appearance-focused structures of the town.

A cheerful and engaging uncle who provides a rare source of warmth for the children during the annual summer festival. While he tells engaging stories about the family history and treats the cousins with genuine kindness, he remains ultimately bound by the same rigid social rules as the rest of the adult relatives.

A distant, spectral presence in the household who rarely speaks or intervenes in family matters. He prioritizes avoiding domestic conflict over protecting his children, making him quietly complicit in the household's abusive dynamics. When he does act, it is typically to enforce patriarchal authority.

Natsuki's childhood friend who completely internalizes the expectations of their suburban town. From an early preoccupation with cute clothes to an adult fixation on marriage and children, she serves as a polite but persistent enforcer of societal norms, constantly questioning Natsuki's unconventional life choices.

The extended network of relatives, including grandparents, aunts, and cousins, who gather annually for the Obon festival. They function collectively as a microcosm of society at large, constantly scrutinizing the children and enforcing behavioral expectations through casual conversation and unified judgment.