Katurian is a writer and slaughterhouse cleaner living under a totalitarian government. He writes macabre stories featuring violence against children, drawing direct inspiration from his highly traumatic upbringing. He cares for his intellectually disabled older brother, viewing himself as Michal's primary protector. Katurian holds a fierce devotion to his writing, insisting his art exists purely for the sake of storytelling rather than political messaging.

Michal is Katurian’s older brother who shares his home. He lives with a severe intellectual disability resulting from years of extreme physical and psychological torture inflicted by their parents. Michal views the world through a highly literal lens, often struggling to separate reality from the fictional events detailed in Katurian's dark stories. He possesses a childlike demeanor that masks the deep psychological damage he carries.

Ariel is a volatile police detective operating within a totalitarian state. He readily adopts an aggressive persona during interrogations, using physical intimidation and verbal threats against suspects. Beneath his explosive anger lies a deep-seated hatred for anyone who harms children. This specific fixation stems directly from severe abuse he suffered during his own childhood.

Tupolski is the lead detective investigating a series of gruesome local crimes. He maintains a cold, indifferent demeanor that contrasts sharply with his partner's explosive rage. Functioning as a bureaucratic enforcer of the state, he views Katurian's subversive stories with intense suspicion. Tupolski prefers to exert strict authority over his investigations and consciously attempts to project total emotional detachment.

The unnamed parents of Katurian and Michal raise their sons in a seemingly normal home before their extremely dark child-rearing methods surface. They view childhood trauma as an acceptable and necessary tool to foster artistic genius in their younger son. Their cruel experiment permanently damages Michal while providing Katurian with the macabre inspiration for his writing.

Ariel's father is an abusive figure from the detective's past. His severe mistreatment of his son fundamentally shapes Ariel's adult worldview, directly motivating the detective's aggressive policing style and his specific obsession with crimes against children.

Tupolski's son is a tragically lost figure from the lead detective's past. His death in an accident represents a significant source of trauma for Tupolski, who goes to great lengths to hide the impact of this loss behind a wall of professional indifference.

The Pillowman is a fictional creation within Katurian’s stories. He is a giant man made entirely of fluffy pink pillows who travels back in time to visit children destined for miserable lives. He attempts to convince these children to end their suffering early, acting as a grim symbol of death offering an escape from a cruel world.