Adolf is a half-French, half-English shopkeeper in London's impoverished Soho district. He sells unbranded birth control, faded pornography, and obscure political pamphlets from his store. Behind this mundane front, he works as a paid informant for an unnamed foreign government. A profoundly lazy man, he prefers the comfort of his domestic routine over active ideological struggle. He socializes with local anarchists and feeds their secrets back to his handlers, prioritizing his own comfort above any political loyalty.

Winnie is Adolf's younger wife and the primary caretaker for her vulnerable brother. She grew up with an abusive father and eventually sacrificed her chance at romantic love to marry Adolf, knowing he could offer a stable home for her dependents. She actively avoids analyzing the world around her, trusting that things are better left unquestioned as long as her family remains safe. She runs the domestic side of the Verloc residence with quiet efficiency.

The Assistant Commissioner is a high-ranking police official who learned his enforcement methods by crushing secret societies in British colonies. He transferred back to London solely to please his wife, leaving him somewhat disconnected from the English domestic policing landscape. He distrusts his own chief inspector and prefers to conduct investigations personally, balancing the demands of the law with the delicate social politics of his wife's elite circle.

Stevie is Winnie's younger brother. He lives with a cognitive disability that makes him entirely dependent on his sister for daily care and protection. He possesses a highly sensitive nervous system and an intense, overwhelming hatred of cruelty. Because he struggles to process everyday violence, from abusive cab drivers to harsh living conditions, he frequently becomes agitated by the injustices of London life.

Mr. Vladimir is the newly appointed First Secretary at a foreign embassy in London. A slim and highly pretentious diplomat, he openly disdains the English middle class for their complacency toward political radicals. He demands that his agents manufacture spectacular, terrifying events to force the British government into passing harsher laws against anarchists.

Ossipon is an imposing former medical student who views the world entirely through trendy pseudo-scientific theories. He presents himself as a committed anarchist but directs most of his energy toward seducing women for financial support. He lacks deep ideological commitment, operating more out of vanity and self-interest than a genuine desire to overturn the social order.

Michaelis is a heavily overweight, idealistic anarchist who spent time in prison for his political actions. He holds a utopian belief that history is moving inevitably toward a peaceful social revolution. Despite his radical rhetoric regarding the poor, he lives comfortably on the charity of an extremely wealthy society woman.

Karl is an elderly man who styles himself as a terrifying, uncompromising terrorist. He frequently advocates for extreme violence and the total dismantling of society, though he has never personally carried out an attack. He is physically frail and relies entirely on his intimidating wife for his daily care.

The Professor is a small, dingy man who builds custom explosive devices for radical groups. Unlike the political anarchists he supplies, he is a true nihilist who desires the total extermination of the weak rather than an egalitarian social reform. He constantly keeps his hand inside his pocket, resting his fingers on a rubber detonator linked to a bomb hidden in his coat.

Heat is a prominent expert in anarchist activity for the Special Crimes Department. He is a pragmatic, working-class policeman who prefers to cultivate stable informants rather than make disruptive arrests. He takes immense pride in his professional standing and fiercely protects his network of underground contacts from his superiors.

Sir Ethelred is the Home Secretary of Great Britain. He is a powerful aristocrat deeply involved in legislative matters. He cares more about the nationalization of the fishing industry than the intricate details of police investigations involving radical groups.

Toodles is Sir Ethelred's young, well-connected secretary. He shares a cynical, wry understanding of the political system with the investigating officers who visit the office, finding quiet amusement in his boss's eccentric legislative priorities.

The Lady Patroness is an extremely wealthy benefactor who uses her vast resources to fund Michaelis. She views him and his radical ideas as an entertaining novelty to amuse her high-society friends, completely secure in the knowledge that her own wealth and status will never truly be threatened.

Winnie and Stevie's mother is an elderly widow who previously ran a boarding house. She deeply appreciates Adolf for taking in her family and rescuing them from poverty. To ease the financial burden on her daughter and ensure Stevie's continued safety, she makes the difficult choice to relocate to a charity house for destitute widows.

Wurmt is a gloomy official at the unnamed foreign embassy. He dislikes Adolf's vague reports about potential unrest, insisting on hard facts and actionable intelligence rather than theoretical predictions.