Lyra is a fiercely independent competitor in the Grandest Game. Her primary goal is winning the prize money to save her family home, Mile's End. She processes information physically and intuitively, often closing her eyes to feel patterns, a reflection of her background as a dancer. Haunted by the childhood trauma of witnessing her father's death, she keeps a strict emotional distance from others.

Grayson is the grandson of puzzle-obsessed billionaire Tobias Hawthorne. Raised to approach life through logic and control, he operates as a methodical strategist within the competition. He possesses a rigid personal code of honor and intense protective instincts toward his family. The game challenges his strict self-control as he develops feelings for Lyra.

Rohan is a cunning and charismatic participant in the Grandest Game. He needs the prize money to pay a massive buy-in fee to become the next Proprietor of a secret society called the Devil's Mercy. He treats trust as a tactical variable and views other players simply as assets or obstacles.

Savannah is a high-society daughter and skilled athlete competing in the game. She holds a deep-seated fury toward the Hawthorne family, believing they are responsible for her father's death. This drive for vengeance dictates her transactional approach to the puzzles and her fellow competitors.

Gigi is Savannah's twin sister and a former competitor in the Grandest Game. She maintains a relentless, weaponized optimism even in dangerous situations. Kidnapped by a mysterious man, she uses her cheerful persistence to interrogate her captor and search for an escape route.

Jameson is a risk-taking sensation seeker who thrives on chaos. As one of the Hawthorne brothers, he actively participates in running the game alongside Avery. He carries a heavy burden of paranoia stemming from a past encounter in Prague, making him intensely suspicious of the current players.

Brady is a quiet, intellectual competitor who previously betrayed his teammates to advance in the game. He carries a photograph of a girl with heterochromia, playing the game under the direction of an unknown sponsor in hopes of finding her. He relies on tracking other players rather than solving puzzles directly.

Eve is the estranged biological daughter of Toby Hawthorne. She holds a personal vendetta against the Hawthorne family and operates from the shadows of the game. She leverages her immense wealth to sponsor participants, using them to sow chaos and inflict emotional damage on her relatives.

Slate is a stoic operative employed by Eve. He kidnaps Gigi under the pretense of protecting her from his employer and other unknown threats on the island. Despite his hardened exterior and history of violence, he displays a conflicted morality regarding his captive.

Avery is the billionaire heiress to the Hawthorne fortune and the architect of the Grandest Game. She designed the competition with the help of the Hawthorne brothers. She serves as the primary target for several characters' grievances, placing her at the center of the island's hidden conflicts.

Nash is the oldest of the Hawthorne brothers. He acts as a stabilizing force for his younger siblings and assists Avery in managing the logistics and security of the Grandest Game.

Xander is the youngest Hawthorne brother. He brings a sense of levity to the high-stakes environment of the island, assisting his brothers and Avery in running the massive puzzle competition.

Odette is a former lawyer for Tobias Hawthorne and an original participant in the Grandest Game. She voluntarily gave up her spot in the competition to Gigi, choosing to step away from the active puzzles.

Knox is Brady's half-brother and a former competitor who was eliminated in the game's initial phase. The Hawthorne family's legal team later hires him to lead a search effort off the island.

Toby is the estranged uncle of the Hawthorne brothers and Eve's biological father. He acts in a supervisory role during parts of the competition and holds dangerous information regarding the death of Savannah's father.

Alisa serves as the dedicated family lawyer for Avery and the Hawthornes. She handles security concerns, manages crisis responses, and coordinates search efforts when individuals go missing from the island.

Alice is the grandmother of the Hawthorne brothers. Thought to be dead, rumors and evidence of her survival heavily impact the current generation, driving much of the paranoia surrounding the game.

Calla is Brady Daniels's missing girlfriend. She is presumed dead by many, but her disappearance serves as Brady's sole motivation for participating in the Grandest Game.

Known as "the Duchess," Zella is a powerful figure vying for control of the secret society called the Devil's Mercy. She operates from afar, targeting Rohan and interfering with his efforts to win the game.