Steven is an isolated 25-year-old man living in a squalid flat under the complete domination of his abusive mother. He works at a local meat-grinding plant in a desperate attempt to build a normal life. His entire conception of happiness comes from watching television sitcoms, which he views as direct instructions for how to live. Terrified of the outside world, he constantly seeks ways to escape his degrading environment.

The Hagbeast is Steven's monstrously abusive mother. Morbidly obese and aggressively cruel, she maintains absolute control over her son through physical violence and verbal degradation. She deliberately feeds Steven revolting, unsanitary meals to keep him weak and polluted. Her entire existence centers on dominating her son and preventing him from achieving any independence.

Lucy is a deeply troubled young woman who recently moved into the building. She harbors a visceral obsession with internal bodily purity, believing that all emotional misery physically accumulates in the intestines as a toxic substance. She uses medical equipment to search for and remove this perceived corruption from her own body. Her desperate attempts to cure her psychological pain make her a grim parallel to Steven's own desire for a clean life.

Cripps is the charismatic and sadistic foreman at the meat-grinding plant where Steven works. He presides over an elite group of workers known as the slaughter party and preaches a philosophy of extreme violence. He believes that killing strips away societal constraints and unlocks a man's true power. He takes an immediate interest in grooming his new employee into this brutal worldview.

The Guernsey is a sentient, talking sienna cow that lives in the city's hidden sewer system. Representing an underground community of escaped livestock, the animal reaches out to Steven during his shifts at the meat plant. It attempts to counter the foreman's violent teachings by warning the young man about the destructive nature of the slaughterhouse philosophy.

Dog is Steven's loyal but severely injured pet. Years earlier, the animal's back legs were paralyzed when the Hagbeast attacked it with a brick. Despite its physical limitations and continuous mistreatment by Steven's mother, the animal remains the only source of pure affection in the squalid apartment.

Gummy is a worker at the meat plant who operates the skull press machine. His face is heavily disfigured with missing lips and teeth, an injury he claims occurred while kissing a cow. He participates in the horrific rituals of the slaughter room and serves as a living warning of the plant's degrading environment.