Billy is a 44-year-old Iraq War veteran and former Marine sniper who works as a contract killer. He operates by a strict moral code, accepting jobs only when the target is definitively a "bad guy." He is highly intelligent and well-read but hides this behind a simplistic facade to keep his employers comfortable. While undercover in Red Bluff for a final lucrative job, he begins writing an honest memoir about his traumatic childhood and military service.

Alice is a 21-year-old business student and part-time barista from Rhode Island. After being drugged and assaulted, she is taken in by Billy, who fears police involvement will ruin his cover. She proves remarkably resilient and observant, quickly deciphering Billy's true identity from television news. She becomes the first reader of his memoir and insists on accompanying him when he leaves town.

Nick is a wealthy casino owner and criminal middleman based in Las Vegas. He typically prefers opulent, glamorous surroundings but operates in the shadows when brokering violence for powerful clients. He projects an attitude of charming camaraderie to keep his contractors compliant and trusting.

Roger is an aging, immensely powerful media magnate whose assets include popular conservative news networks. He uses his vast wealth to indulge in horrific abuses of power, specifically targeting young children. He operates entirely from the shadows, employing fixers and hitmen to eliminate anyone who threatens to expose his crimes.

Bucky is a skilled financial broker who manages money and arranges jobs for contract killers. He specializes in creating pristine, untraceable identities for his clients. He maintains a remote cabin in Sidewinder, Colorado, where he lives under his real name, Elmer Randolph, embracing a quiet life far removed from his criminal enterprises in New York.

Joel is an incarcerated contract killer facing severe charges, including the sexual assault of a writer and first-degree murder. He attempts to leverage incriminating evidence against a powerful media mogul into a plea deal to commute a potential death penalty. His upcoming transfer to the Red Bluff courthouse makes him the primary target of Billy's mission.

Kenneth is a local businessman in Red Bluff who serves as the on-the-ground contact for Billy's contract. He owns the 22-story Gerard Tower situated directly opposite the courthouse. He suffers from severe financial distress due to failed real estate ventures and multiple divorces, making him desperate and compliant.

Giorgio, often referred to as Georgie Pigs, is Nick Majarian's trusted right-hand man. He assumes the alias George Russo, a literary agent, to help legitimize Billy's presence in Red Bluff. He manages the lease for Billy's office space and acts as a handler, passing along coded messages about the target's arrival.

Jamal is a friendly, welcoming neighbor living next door to Billy's undercover residence in Red Bluff. He works at a local tire store and lives with his wife and two young children. His frequent invitations to community gatherings complicate Billy's efforts to remain emotionally detached from the town.

Shanice is the eight-year-old daughter of Jamal and Corrie Ackerman. She forms a sweet, innocent bond with Billy, who wins her a stuffed flamingo top prize at a local carnival. She names the toy Dave after Billy's alias and draws him a picture of it.

Cathy is Billy's younger sister, murdered at age nine by their mother's abusive boyfriend over burned cookies. Her tragic death serves as the defining trauma of Billy's life, directly forming his strict moral code regarding who deserves violence.

Darlene is Billy and Cathy's mother, raising them in a trailer park. Following the murder of her daughter, she refuses to accept responsibility for bringing a violent man into their home. Overwhelmed by poverty and grief, she succumbs to severe alcoholism and meth addiction, resulting in Billy's placement in foster care.

Bob is Darlene's abusive boyfriend from Billy's childhood. He routinely beats Darlene and her children, eventually murdering nine-year-old Cathy in a rage. He is shot and killed by an eleven-year-old Billy in an act of self-defense.

Tripp is a 24-year-old man who leverages a casual interaction at a cafe to invite Alice Maxwell to his apartment. He makes her a drugged drink and participates in a brutal gang assault against her alongside his roommates, leading Billy to track him down.

Frank, also known as Frankie, is one of Nick Majarian's loyal enforcers. He assists with the security and logistics surrounding Billy's arrival in Red Bluff and attends Nick's dinner party. He relies heavily on physical intimidation in his line of work.

Marge is Frank Macintosh's mother. She works for Nick Majarian in a dual capacity, managing domestic tasks while also acting as an armed guard at the entrance to his Promontory Point estate. She is fiercely protective of her son.

Don lives with his wife Beverly above the basement apartment Billy rents in his Dalton Smith persona. He harbors racist political anxieties and keeps a firearm in his apartment. He inadvertently aids Billy's evasion plans by leaving town suddenly to take a cruise.