Armand is a middle-aged, happily married man who recently stepped down as head of the province-wide police force to live quietly in Three Pines. He possesses a keen ability to notice small details and maintains a calm, objective demeanor even in highly tense situations. Despite his retirement, his investigative instincts compel him to look closely into the village's disturbing recent events.

Jean-Guy is a high-ranking police agent who lives in Montreal with his family. He maintains a close personal and professional bond with his father-in-law, Gamache, relying on his mentorship while taking charge of the official investigation. He approaches police work with a pragmatic, procedural mindset.

John is a notorious serial killer who has been imprisoned in a maximum-security facility for nearly two decades. His horrific crimes were largely suppressed from the public through a secret trial. Despite his incarceration, his past actions and written words continue to spread fear and influence the outside world.

A retired physics professor from McGill University, Michael specializes in massive artillery. He dresses innocuously in a tweed jacket and bow tie, masking a sharp intelligence. He shares a complicated past with Gerald Bull and holds grudges against the Canadian intelligence agents who restrict his access to research files.

Al is a resident of Three Pines who performs folk music and lives a quiet life with his family. He presents himself as an American draft dodger who relocated to Canada for ideological reasons. He loves his son deeply and struggles to cope with the sudden scrutiny directed at his family following Laurent's discovery.

Ruth is an elderly, famous poet who has lived in Three Pines for decades. She behaves erratically, frequently uses profanity, and keeps a pet duck as a companion. Beneath her abrasive exterior, she harbors deep anxieties regarding the village's history and the unexpected emergence of the controversial play.

Clara is a highly successful and talented painter residing in Three Pines. She is currently processing the grief of losing her husband, Peter, which stalls her creative output but heightens her empathy for others experiencing tragedy. Her artistic eye allows her to notice visual details that others overlook.

Laurent is an imaginative nine-year-old boy who constantly carries a carved wooden stick. He frequently invents wild stories, leading the adults in Three Pines to dismiss his claims. His discovery in the woods shatters the tranquility of the village and initiates a major police investigation.

Antoinette is an active community member who organizes the local production of a controversial play. She inherited her current home and various papers from her late uncle, Guillaume Couture. She stubbornly defends her choice of script despite intense pressure from the community and Gamache.

Brian co-directs the amateur theatrical production in Three Pines with his partner, Antoinette. He lives in the home she inherited from her uncle and frequently travels to Montreal. He displays a strong interest in the historical rumors surrounding long-lost weapons.

Isabelle is the lead investigator for the provincial police force assigned to the case in Three Pines. She respects Gamache's expertise and consults him informally despite his retired status. She pushes for practical information, sometimes leaking details to the public to track suspect reactions.

Mary is a quiet, unassuming file clerk for the Canadian intelligence agency, CSIS. She manages the classified files concerning Gerald Bull and his research. She insists on prioritizing national security over local law enforcement concerns, frequently clashing with Gamache's investigative methods.

Sean is a CSIS agent who travels to the village to secure information regarding the discovery in the woods. Like Mary, he knows extensive details about the history of Canadian weaponry and actively discourages the local police from making their findings public.

Reine-Marie is Gamache's wife, sharing his quiet retirement in Three Pines. She possesses strong research skills and independently digs into historical archives to support her husband's informal inquiries. She provides emotional stability for Gamache as he processes the dark events unfolding in the village.

Gerald is a deceased, historically famous engineer who developed long-range artillery. He operated an international consulting business and engaged in highly controversial projects before his assassination in 1990. His legacy and missing research drive the central conflict in Three Pines.

Guillaume was a talented engineer who collaborated with Gerald Bull on artillery projects. He built a large home near Three Pines, which he eventually passed down to his niece, Antoinette. His quiet, undocumented work on major weapons projects leaves a dangerous legacy.

Myrna is a former psychologist who currently operates the bookstore in Three Pines. She uses her background in psychology to analyze the community's reaction to the controversial play, helping her friends work through their ethical dilemmas regarding the production.

Evie is Laurent's mother and lives a quiet life with her husband, Al. She actively encourages her son's artistic interests and displays a deep, unconditional love for him. The sudden tragedy in the woods thrusts her into unwanted scrutiny from the police and the community.

Gabri runs the local bed and breakfast in Three Pines. He is deeply embedded in the village's social network and becomes a strategic conduit for information when the police need to carefully leak news to the wider community.

Clement is an elderly resident who owns the local grocery store. He has lived in Three Pines long enough to remember the events of the 1980s and shares a hidden, uncomfortable history with Ruth regarding the construction projects in the nearby woods.

Adam is a young police agent who displays fierce loyalty to Gamache. He possesses valuable experience working within the maximum-security prison system and uncovers critical background information regarding the residents of Three Pines.

Peter was an artist and long-time resident of Three Pines. His recent death deeply affects his wife, Clara, influencing how she views the unfolding tragedies in their community.

Olivier runs the bistro in Three Pines with his partner, Gabri. His business occupies a renovated building that formerly housed the local hardware store, a detail that unexpectedly proves useful during the investigation.

Annie is Gamache's adult daughter and Jean-Guy's wife. She represents the peaceful, domestic future her father and husband desperately wish to protect from the violence they encounter in their police work.