Equality 7-2521 is a 21-year-old Street Sweeper living in an oppressive collectivist city. Standing unusually tall at six feet, he physically stands out in a society that demands uniformity. He possesses an inherently curious and analytical mind, which makes him long for a position in the Home of the Scholars. He actively conducts unauthorized scientific experiments in secret, driven by a desire to understand the natural world.

Liberty 5-3000 is a 17-year-old Peasant assigned to agricultural work outside the city. She maintains a stoic and fearless demeanor, holding her head high while working in the dirt. She silently rebels against the strictures of her society by exchanging forbidden glances with Equality 7-2521, eventually speaking with him directly.

Collective 0-0009 is the oldest member of the World Council of Scholars. He acts as the primary voice of the collective authority, fiercely defending the status quo and reacting with hostility to any sign of independent thought. He actively suppresses unsanctioned innovation to maintain societal control.

International 4-8818 is a tall, strong Street Sweeper and a member of Equality 7-2521's work crew. He possesses a naturally joyful disposition and faces ostracization for smiling and drawing, behaviors deemed inappropriate by the state. When he and Equality 7-2521 find a hidden tunnel, he demonstrates profound loyalty by choosing to protect the secret despite his fear of authority.

Fraternity 2-5503 is a quiet Street Sweeper with kind eyes who works in the same vocation as Equality 7-2521. He suffers from sudden, unexplained bouts of crying throughout the day and night. His sorrow illustrates the psychological damage inflicted by the city's rigid collectivist system.

Solidarity 9-6347 is a bright youth assigned to work as a Street Sweeper. While he appears fearless and functional during his waking hours, his suppressed psychological distress manifests at night. He suffers from severe night terrors, screaming for help while he sleeps.

Union 5-3992 is a Street Sweeper assigned to the same work crew as Equality 7-2521. He suffers from a neurological condition that causes him to experience convulsions. The authorities view him as an ideal citizen because his intellectual limitations ensure his complete compliance with the collective.

The Saint of the Pyre is the title Equality 7-2521 secretly gives to an unnamed man who was publicly burned at the stake. The authorities executed him for discovering the forbidden Unspeakable Word. The man's calm and defiant demeanor during his death deeply impacts a young Equality 7-2521.