Aiden is a man trapped in a supernatural prison at Blackheath manor. He is forced to relive the same day repeatedly, occupying the bodies of eight different hosts to gather clues. He retains no memories of his true identity or his past outside the estate. Driven by a strong moral compass and a chivalric need to protect others, he works frantically to solve a murder so he can secure his freedom.

Anna is a fellow participant in the mystery playing out at Blackheath. She appears as a petite, unremarkable young woman wearing a maid's uniform, which allows her to move through the house largely unnoticed. She retains some knowledge of the game's rules and communicates with Aiden using carved chess pieces, acting as his primary confidante.

The Plague Doctor is an enigmatic overseer of the game at Blackheath. He wears a heavy black greatcoat and a porcelain beak mask that completely obscures his features. He acts as an administrative guide, determining the sequence of Aiden's host bodies and monitoring his progress, though he claims he does not actually know the identity of the murderer.

Evelyn is the glamorous, striking daughter of Lord and Lady Hardcastle. She has recently returned from exile in Paris to attend a masquerade ball hosted in her honor. She carries a small pistol, openly despises the upper-class society surrounding her, and suspects her parents have summoned her back simply to punish or humiliate her. Her impending murder at 11:00 PM is the central puzzle Aiden must solve.

Daniel is a confident, assertive guest at the Blackheath gathering. He quickly identifies Aiden and helps calm him down, later claiming to be one of Aiden's future host bodies. He steps in to stop bullying among the guests and presents himself as a valuable ally who already possesses knowledge of events yet to occur.

The Footman is a brutal, sinister figure who actively stalks Aiden and Anna through the Blackheath estate. He acts as a direct physical threat, attempting to murder Aiden's hosts before they can solve the mystery. He uses psychological terror, referring to his targets as rabbits and leaving grotesque warnings.

Lord Peter is the patriarch of the Hardcastle family and the master of Blackheath. He is hosting the masquerade ball on the exact nineteen-year anniversary of his youngest son's murder. He struggles with severe financial issues and attempts to use his daughter's impending marriage to secure his estate's future.

Lady Helena is the matriarch of the Hardcastle family. She has a cold, strained relationship with her daughter Evelyn, having banished her to Paris following the death of her youngest son, Thomas. She orchestrates a highly lucrative but loveless engagement for Evelyn to save the family from ruin.

Michael is the heir to Blackheath and Evelyn's older brother. He provides Aiden with crucial background details regarding the murder of his younger brother, Thomas, nineteen years prior. He appears highly anxious about his sister's well-being and frequently searches the grounds for her.

Thomas is the youngest child of the Hardcastle family, murdered at age seven near the estate's lake nineteen years before the current events. His tragic death fundamentally fractured the family, resulting in Evelyn being blamed and sent away to Paris.

Sebastian is a medical physician and drug dealer who serves as Aiden's very first host body. He abuses his medical privileges to supply drugs to wealthy clients, a fact that deeply disgusts Aiden once he learns of it.

Dickie is a physician attending the masquerade ball at Blackheath. He provides medical care to the guests and notes the knife wounds on Aiden's arm early on, warning him that he is in significant danger and should leave the estate.

Mr. Collins is the stoic butler at Blackheath, notable for severe burn scars on his face. He is heavily involved in managing the chaotic household and serves as Aiden's second host body, dropping Aiden into the physical pain of a recent beating.

Ted is a former estate servant who mysteriously acquired vast wealth and property after claiming to interrupt the murder of Thomas Hardcastle years ago. He now attends the ball as an aggressive, entitled guest who blackmails the family and terrorizes the household staff.

Lord Ravencourt is an older, physically grotesque, and extremely wealthy man. The Hardcastle parents have arranged for him to marry Evelyn and purchase the Blackheath estate to relieve their financial debts. He serves as Aiden's fourth host body.

Charles works as the personal valet to Lord Ravencourt. He is highly intelligent and observant, helping Aiden gather clues and investigate the estate's guests. He implies early on that he possesses a scandalous personal connection to the Hardcastle family.

Madeline is Evelyn's personal maid. She acts as a quiet messenger between the guests and frequently accompanies Evelyn on the estate grounds, relying on Evelyn for protection against aggressive male guests.

Lucy is a young maid working at Blackheath. She suffers routine abuse from the cruel guests, specifically Ted Stanwin, highlighting the severe class disparities present at the estate.

Millicent is a wealthy guest attending the party with her adult son. She frequently gossips about the estate's staff and the Hardcastle family secrets, while fiercely protecting her own son from the consequences of his violent actions.

Jonathan is Millicent Derby's wealthy, entitled son. He is a violent predator who aggressively pursues the female staff at the manor. He serves as Aiden's fifth host body, forcing Aiden to constantly fight back against his host's dark physical urges.