Sam is a sarcastic, distrustful fifteen-year-old who feels cursed by a history of accidents surrounding her. She has just relocated to Salem to offset the medical costs for her comatose father. As a descendant of Cotton Mather, she faces immediate hostility from locals who blame her lineage for the Salem Witch Trials. She wears black clothing unintentionally, mimicking her Puritan ancestors, and uses her sharp wit as a defense mechanism against a hostile new school.

Vivian is Sam's assertive, fashion-conscious stepmother who recently moved the family to Salem to afford her husband's medical bills. She wears loud, high-heeled shoes and desires to be admired by those around her. Since Charles fell into a coma, her relationship with Sam has deteriorated into frequent, tense arguments.

Jaxon is Sam's handsome teenage neighbor who provides a welcoming contrast to the hostility she faces at school. He acts as her guide to modern-day Salem, sharing local history and providing steadfast support against bullies. He views things practically and firmly disbelieves in ghosts or curses.

Elijah is an arrogant but handsome spirit bound to the Mather house who lived during the time of the Salem Witch Trials. He is highly educated, artistic, and possesses historical knowledge crucial to understanding the town's curses. He initially clashes with Sam due to mutual distrust but shares a connection with her regarding feelings of isolation.

Lizzie is the older ringleader of a clique known as the Descendants. She has heterochromia and holds deep-seated anger toward the Mather family for their historical role in the witch trials. She aggressively bullies Sam and blames her for the unfortunate events occurring in Salem.

Mrs. Meriwether is a warm, cheerful neighbor who owns a local bakery and acts as a surrogate mother figure to Sam. She was a childhood friend of Sam's father, Charles, and provides comforting stories about his past. Her welcoming nature and test kitchen offer Sam a refuge from the tense environment of the Mather household.

Susannah is a member of the Descendants who displays more empathy and emotional awareness than her peers. Unlike the rest of her clique, she treats Sam with cautious curiosity rather than immediate hostility. She worries deeply about her younger sister, who has cancer, and understands the weight of Salem's dark history.

John is the sole male member of the Descendants clique. He acts as the physical muscle for Lizzie's bullying tactics. He intensely dislikes Sam due to her lineage and frequently attempts to intimidate or provoke her in the school hallways.

Alice is a member of the Descendants who strictly adheres to the group's gothic aesthetic. She fiercely honors her ancestors who were persecuted during the Salem Witch Trials and immediately shuns Sam upon learning her last name.

Mary is a member of the Descendants who presents a dark, unified front with her friends at school. Despite her intimidating public persona and participation in the clique's bullying, she comes from a normal, comfortable home environment.

Charles is Sam's loving father who has mysteriously fallen into a coma, prompting the family's relocation to Salem. He grew up in Salem but distanced himself from the town and his own mother due to lingering tensions. He provides Sam with her only sense of true familial support.

Abigail is Elijah's sister who lived in the Mather house during the Puritan era. She loved music and singing, which defied the strict societal rules of her time. Her history is detailed in hidden letters discovered by Sam in an antique armoire.

Cotton Mather is a historical Puritan minister and Sam's direct ancestor. His written works and sermons heavily influenced the mass hysteria of the Salem Witch Trials. His legacy casts a dark shadow over Sam's life in modern-day Salem.