Jasper, known as Jazz, is the seventeen-year-old son of the nation's most notorious serial killer. He lives in Lobo's Nod with his grandmother and possesses an unsettling, encyclopedic knowledge of police procedures and crime scenes. Haunted by memories of his father and recurring nightmares, he tries to prove he is nothing like his dad by hunting a new serial killer in his town. He frequently relies on his ability to read people and manipulate situations to conduct his own unofficial investigations.

Billy Dent is an infamous serial killer responsible for over one hundred murders, currently serving time in Wammaket State Penitentiary. Known by monikers like the Artist and Green Jack, he possesses extreme intelligence and a manipulative charm that allowed him to blend into society for years. He brainwashed and trained his son in the methods of murder, leaving a lasting psychological scar.

The Impressionist is an unidentified serial killer who has recently arrived in Lobo's Nod. He operates methodically, mimicking the specific crime patterns and victim profiles of Billy Dent. He blends in perfectly with average citizens, hiding his violent nature behind an ordinary facade while taking body parts as trophies from his victims.

G. William Tanner is the respected local sheriff of Lobo's Nod. He gained prominence four years ago as the officer who discovered Jazz and arrested Billy Dent. He cares about Jazz's well-being and urges him to live a normal teenage life, consistently rejecting the boy's requests to help with official police investigations.

Howie is a tall, gangly teenager and Jazz's closest friend. He suffers from Type-A hemophilia, meaning he bleeds profusely from minor injuries and requires frequent clotting factor injections. He relies on humor to diffuse tense situations and acts as a loyal, grounding presence in Jazz's chaotic life.

Connie is an aspiring actress and high school student participating in the school's production of *The Crucible*. She provides emotional stability for Jazz, constantly reminding him that his father's actions do not determine his future. She is fiercely protective of him but worries about the danger his obsession with serial killers brings.

Gramma Dent is Jazz's elderly, dementia-stricken grandmother who raised Billy Dent in the same house where she now lives with her grandson. Her mental state fluctuates between childlike confusion and aggressive, violent outbursts. She harbors deep-seated resentments and frequently taunts Jazz about his genetic predisposition toward evil.

Melissa is a local social worker assigned to monitor Jazz's living conditions. She views Gramma Dent's deteriorating mental state as a serious threat to a teenager's well-being. She makes frequent, unannounced visits to the property and actively pushes to have Jazz placed in the foster care system.

Doug Weathers is a local news reporter who rose to minor prominence covering Billy Dent's arrest. He actively seeks to exploit the new string of murders for media attention, frequently harassing Jazz and his friends for exclusive interviews and sensational photographs.

Erickson is a deputy in the Lobo's Nod police department. He catches Jazz and Howie sneaking around the morgue and frequently acts as an enforcer for Sheriff G. William Tanner.

Jeff Fulton introduces himself as the father of Harriet Klein, the eighty-third victim of Billy Dent. He appears haggard and defeated, approaching Jazz in hopes of discovering his daughter's final words to gain closure.

Virginia "Ginny" Davis is the new drama teacher at Lobo's Nod High School. She directs the student production of *The Crucible* and encourages Jazz to participate in the cast, providing a brief sense of normalcy in his routine.

Initially identified only as Jane Doe, Fiona is a young woman whose murder initiates the town's panic. The specific nature of her injuries matches the early methods used by Billy Dent.

Helen is a waitress at the Coff-E Shop where Jazz and Howie meet before school. She becomes a target in the escalating series of copycat murders occurring around Lobo's Nod.