Jameson is the 19-year-old third-born grandson of the deceased billionaire Tobias Hawthorne. Restless and constantly seeking new challenges, he possesses an intense love for games, risk, and high-stakes puzzles. When approached by a man claiming to be his father, Jameson eagerly jumps into a secretive London underground competition, viewing it as a way to prove his worth and keep his mind occupied.

Grayson is the 20-year-old second-born grandson of Tobias Hawthorne. Raised to believe he would inherit the family empire, he acts as the stoic, perfectly tailored protector of his family. He travels to Phoenix to handle a crisis involving the half-sisters he has never truly met, determined to fix their problems while keeping his emotional distance.

Avery is the 18-year-old heiress to the massive Hawthorne fortune. She is establishing a foundation to give away the majority of her wealth. Quick-witted and intensely loyal, she uses her newfound social capital to help Jameson infiltrate the secretive Devil's Mercy club, insisting on partnering with him rather than letting him take risks alone.

Gigi is the 16-year-old daughter of Sheffield and Acacia Grayson. Described as a human ray of sunshine with wavy brown hair, she uses her bubbly personality to disarm people. She is actively investigating her missing father's secrets, showing a surprising talent for picking locks and gathering clues.

Savannah is Gigi's 16-year-old twin sister. She presents an icy, controlled exterior, dressing impeccably in pleated skirts and heels while maintaining her skills as an athlete. She harbors deep suspicions about Grayson's presence in Phoenix and acts as the primary protector of her family's vulnerable state.

Ian is a professional gambler in his mid-forties and the third-born son of an elite British family. He reaches out to Jameson with a specific agenda: recruiting him to enter the exclusive Devil's Mercy club to win back the family's ancestral home, Vantage, which Ian lost.

Simon is the eldest son and heir of the Earl of Wycliffe, operating in underground circles under the title Viscount Branford. With thick red hair and stern features, he takes his position as the head of his family seriously and enters the Game with his own hidden motives.

Zella is a Black woman in her mid-twenties who holds the title of duchess. Equipped with a clipped British accent and a dry sense of humor, she navigates the elite, male-dominated spaces of London high society with sharp intelligence and calculated risks.

Rohan is the Factotum, the right-hand man and presumptive heir to the owner of the Devil's Mercy. He coordinates the club's operations, sets the terms for Avery's entry, and designs the high-stakes Game played at the Vantage estate.

Nash is the 24-year-old eldest Hawthorne brother. He calls his siblings together using their emergency text system to announce his engagement. He frequently acts as the emotional anchor for his younger brothers, offering advice and keeping a watchful eye on Grayson's operations.

The youngest Hawthorne brother, Xander provides technical assistance and lighthearted commentary to his siblings. He assists Grayson in decoding clues and tracking down background information for his investigation in Phoenix.

The deceased billionaire patriarch of the Hawthorne family. His demanding expectations, complex rules, and intricate puzzles heavily influenced the psychological development of his four grandsons, leaving lasting impacts on how they handle pain, love, and loyalty.

The biological father of Grayson, Gigi, and Savannah. His past actions, including embezzlement and his intense focus on avenging his nephew, severely fractured his family and left his daughters searching for answers in the wake of his disappearance.

The mother of Gigi and Savannah, and wife to Sheffield. Facing an FBI investigation and completely depleted financial accounts, she attempts to hold her family together while maintaining grace under immense pressure.

The heir to the Blake fortune, she operates with a sense of entitlement and deep insecurity. She tracks Grayson's movements in Phoenix, attempting to leverage his secrets regarding his half-sisters as part of her ongoing rivalry with the Hawthornes.

The Grayson family lawyer and executor of the twins' trusts. A former rival for Acacia's affection, he uses his legal position and control over the family's assets to exert pressure on Acacia during her financial crisis.

The son of lawyer Kent Trowbridge. He dates Savannah Grayson, though he exhibits controlling and pushy behavior toward her, aligning with his father's broader plans to tie their families together.

The enigmatic and powerful owner of the Devil's Mercy club. He orchestrates high-stakes bets and requires deeply valuable, dangerous secrets as the price of admission to his annual Game.

Avery's older sister. She provides emotional grounding for the Hawthorne brothers and remains a constant, supportive figure in Avery's rapidly changing world of wealth and puzzles.

A competitor in the Proprietor's Game, employed by Bowen, the eldest Johnstone-Jameson brother. She is a ruthless player who attempts to goad Jameson and secure the prize by any means necessary.