Ophelia is the 23-year-old heir to the Grimm family legacy in early 20th-century New Orleans. With distinctive blue eyes and powerful necromancy abilities, she sees ghosts and Apparitions that remain invisible to ordinary humans. She lives with obsessive-compulsive disorder, which takes the form of the Shadow Voice, an internal entity that demands she perform repetitive compulsions. Fiercely protective of her younger sister, she enters the lethal Phantasma competition to secure her safety.

Blackwell is a Phantom trapped within the walls of Phantasma, appearing as a tall man with striking white hair and bright green eyes. He has no memory of the world outside the games because his memories are wiped clean between each competition cycle. Seeking a way to break his tether to the manor, he targets Ophelia to form a blood bargain, offering his supernatural protection in exchange for her help in finding his freedom.

Genevieve is Ophelia's younger sister, a free-spirited young woman who retains her natural turquoise eyes rather than the inherited Grimm Blue. Feeling guilty over the immense pressure placed on Ophelia, she secretly keeps her knowledge of their mother's massive financial debts hidden. Hoping to save Grimm Manor and solve their impending ruin, she rashly enters the deadly competition on her own.

Cade is a ruthless and self-serving contestant sent by his family to win the Devil's Grant and solve their financial troubles. He views the other competitors strictly as obstacles rather than allies. He lacks empathy entirely, willing to put others in lethal danger to benefit his own chances of surviving the trials.

Sinclair is a Devil trapped inside Phantasma. Characterized by his fair complexion, dark hair, and feline-like red eyes, he utilizes illusions and manipulation to toy with the mortal contestants. He harbors a deep resentment toward Blackwell and actively tries to undermine his blood bargains and sabotage his attempts to escape.

Tessie is the late mother of Ophelia and Genevieve, and the former head of the Grimm family's necromancy practice. During her life, she subjected Ophelia to rigorous, isolating magical training to prepare her for the family legacy. Her sudden death uncovers a trail of hidden debts and secrets that push her daughters into the dangerous path of the Devil's Manor.

Gabriel is the father of Ophelia and Genevieve, a Specter with the ability to turn invisible and incorporeal. He is an absent figure in his daughters' lives, though Genevieve's discovery of old letters points to his profound obsession with their mother and his deep ties to the history of the Devil's Manor.

The Shadow Voice is the psychological manifestation of Ophelia's obsessive-compulsive disorder. It dwells within her mind, constantly threatening her with intrusive thoughts of violence and tragedy unless she completes specific repetitive tasks, such as knocking three times. It feeds on her fears and isolation, heavily shaping her deep-seated insecurities.

Luci is a participant in the Phantasma games who quickly establishes a warm rapport with Ophelia. Unlike many of the more aggressive competitors, she attempts to maintain her humanity during the trials. She secretly holds feelings for another contestant, putting her at direct risk of the manor's curse against romance.

Leon is a contestant who draws Luci's romantic attention. He attempts to survive the deadly trials while managing the dangerous reality that forming emotional attachments within the Devil's Manor carries severe, cursed consequences.

Beau is a contestant who aligns himself closely with Cade Arcenaux. He acts as Cade's aggressive backup, sharing his hostility toward Ophelia and viewing the other competitors with suspicion and disdain.

Eric is a wealthy competitor who enters the games to secure the Devil's Grant, hoping to use it to save his father from tax evasion charges. He represents the greed and desperation that draws people to the lethal trials.

Edna is a determined contestant participating with the specific goal of using the Devil's Grant to bring her deceased brother back to life. Her singular focus makes her a tragic figure within the violent reality of the games.

Jasper is one of the Devils who helps orchestrate the challenge levels. He enjoys taunting the trapped Phantoms and offering his own dubious, high-stakes deals to the desperate mortal competitors attempting to survive the manor.

Raeya is a beautiful and dangerous Devil working within the games. She manages specific challenge levels and shares a complicated history with Blackwell, using her position to incite jealousy and control the flow of information to the mortal participants.

Drima is a Devil responsible for running the Lust level of the games. She possesses a terrifying control over her domain, swiftly and violently punishing any mortal who steps out of line or disrespects her authority.

Zel is a horned Devil tasked with introducing the first trial. He acts as a grim herald for the horrors to come, laying out the lethal stakes of the competition for the newly arrived mortals.

Farrow is an acquaintance of Genevieve Grimm in New Orleans. Though he stood her up for a ball in the past, rumors suggest he plans to enter the Devil's Manor, demonstrating how the temptation of the Devil's Grant reaches across the city's social circles.