A young woman residing with Godwin Baxter. She possesses an adult body but exhibits a childlike mind that develops at a remarkably rapid pace. Highly curious and frank, she approaches the world without conventional societal filters or Victorian inhibitions. She expresses a strong eagerness to experience life, travel, and understand her surroundings, often overwhelming the men who try to manage her.

A Scottish public health officer and doctor who grew up in poverty as the illegitimate son of a Galloway farmer. He attends medical school in Glasgow and eventually befriends the brilliant Godwin Baxter. Archibald acts as the primary narrator of the manuscript, documenting his fascination with Godwin's medical experiments and his immediate infatuation with Bella.

A brilliant, unconventional scientist and medical researcher. The illegitimate son of the renowned Sir Colin Baxter, Godwin possesses an imposing physical frame and a shrill voice that frightens many patients away from his practice. He maintains radical ideas about medicine and society, devoting his private time to highly experimental biological procedures in his home laboratory.

A slick lawyer based in Glasgow with an unapologetic appetite for hedonism. He harbors a strong preference for working-class women and becomes intensely infatuated with Bella's uninhibited nature. He facilitates her desire to travel and experience the world, though his stamina and resources are quickly tested by her boundless energy.

A fictionalized version of the real-world author who acts as the enthusiastic editor of Archibald's manuscript. He firmly believes the extraordinary events detailed in the text are factual and historical, providing extensive footnotes to support his claims while dismissing contrary evidence.

A Glaswegian historian who finds Archibald's manuscript in the 1970s. Unlike Gray, Donnelly approaches the text with academic skepticism, viewing the manuscript strictly as a work of fiction and disagreeing with Gray's insistence on its historical accuracy.

An English traveler who subscribes to pessimistic, Malthusian political views. He believes that suffering is inevitable and attempts to educate Bella in his cynical worldview, trying to convince her to accept society's cruelties rather than attempting to change them.

An American Protestant and former missionary in China. He espouses imperialist theories and believes in civilizing the world through colonialism. He actively tries to rid Bella of her childlike innocence by exposing her to the stark realities of poverty and desperation in Alexandria.

The manager of a brothel in Paris who originally hails from Manchester. She is delighted to speak English with Bella and offers her a position working at the establishment when her funds run low.

A sex worker employed at Madame Cronquebil's establishment in Paris. She shares socialist ideals and befriends Bella during her brief employment there, discussing politics and society.

An authoritative, domineering army general from England. He maintains strict, traditional views regarding female behavior and societal roles, demanding absolute obedience and propriety from the women in his life.

A man from Manchester who escaped poverty through cunning and hard work to amass a substantial fortune. He views women primarily in terms of their ability to secure advantageous social positions and shows little concern for their personal autonomy.

An older woman who resides in Godwin Baxter's household. She manages the property's domestic affairs and helps attend to the daily needs of Godwin and Bella.

A medical adviser who adheres to strict, conservative Victorian medical views regarding women's health and psychology. He fully supports using physical intervention to manage women deemed hysterical or uncooperative.

A solicitor working for General Blessington who uses his legal expertise to argue for his client's rights and authority over domestic matters, operating strictly within the confines of Victorian patriarchal law.

A detective hired to investigate disappearances and track down missing individuals across the United Kingdom. He gathers the information that leads General Blessington to Glasgow.