Charlie is an eight-year-old girl who possesses extraordinary pyrokinetic abilities, an unintended result of her parents participating in a college drug trial years before her birth. Her parents instill a deep sense of fear and guilt in her regarding these powers, referring to her fire-starting as the "Bad Thing" to keep her from hurting herself or others. She relies entirely on her father for safety and guidance as they run from the Shop. Despite her destructive potential, she maintains a strong, instinctual sense of right and wrong.

Andy is Charlie's father and a survivor of the Lot Six pharmacological trials, which gave him a mild telepathic ability he calls a "push." He uses this power to protect his daughter from the Shop, even though overusing it causes him severe physical pain and small brain hemorrhages. He acts out of deep parental devotion, taking extreme measures to hide his daughter from the government. He continually questions the ethics of controlling Charlie's abilities while depending on them for survival.

Rainbird is a heavily disfigured, methodical assassin employed by the Shop. He possesses a cold detachment and an obsessive interest in the exact moment of death, constantly observing the eyes of his dying victims. Independent of his government employers, he develops his own chilling agenda regarding Charlie. He relies on psychological tactics and false empathy to bring targets closer to him before he strikes.

Captain Hollister is the aging, conservative director of the Shop, a secretive government intelligence agency. He focuses entirely on maintaining control and suppressing public knowledge of the disastrous Lot Six trials. Viewing the McGee family strictly as dangerous anomalies, he believes they must be contained or eliminated for national security. His absolute authority masks the moral decay at the center of his organization.

Vicky is Andy's wife and Charlie's mother, who met her future husband during a university drug trial. She survived the pharmacological testing alongside Andy, gaining mild telepathic abilities in the process. She worked alongside Andy to raise Charlie, attempting to suppress their daughter's dangerous powers by instilling a deep fear of using them.

Dr. Wanless is the leading scientific expert who oversaw the disastrous Lot Six trials years prior. He intimately understands the science behind Charlie's abilities and warns the Shop that her power could grow to rival a nuclear weapon. He provides the agency with strategies for breaking down psychological barriers, demonstrating a clinical detachment from the human cost of his experiments.

Irv is a pragmatic rural farmer who takes pity on a hitchhiking father and daughter. Distrustful of federal authority and aware of rumors regarding secret drug trials, he readily believes Andy's wild story. He offers his home and resources to the fugitives, standing up to the government agents who arrive at his property.

Norma is Irv's wife and a welcoming presence on their rural farmstead. She kindly takes Charlie to see the chickens, completely unaware of the supernatural and governmental dangers closing in on her home.

Eddie is a soldier whose highly aggressive, misogynistic internal thoughts are inadvertently overheard by Charlie's burgeoning telepathy. He serves as an early catalyst for her powers, experiencing her defensive reaction firsthand.

Mrs. Gurney is a woman who previously hired Andy to help her lose weight using his telepathic push. She becomes a symbolic figure in his mind representing willpower and the fight against substance dependency.

James Richardson is a newly appointed point man for the Shop, brought in to take over the active search for the McGees. He represents the fresh, aggressive tactics the agency employs to secure their targets.

Dr. Hockstetter is one of the primary medical professionals employed by the Shop. He assists in the careful planning, observation, and eventual testing of the agency's human subjects.

Necromancer is a large black horse that Charlie is permitted to ride as a reward for cooperating with the Shop. The animal represents sheer physical power and offers Charlie a rare, uncomplicated bond free of human manipulation.

Tarkington is a shadowy government agent who tracks the aftermath of the Shop's destruction. He represents the persistent, unyielding surveillance of federal authority, even when a subject attempts to break free.