Diana is an American historian and tenured professor at Yale University who studies seventeenth-century chemistry. As the descendant of the first witch executed at Salem, she possesses latent magical abilities that she consciously represses. Following the murder of her parents when she was seven, she relies entirely on science and logic rather than spells. Her discovery of the enchanted manuscript Ashmole 782 forces her to confront the magical world she tries to avoid.

Matthew is a 1,500-year-old vampire working as a professor of biochemistry and genetics. He studies the evolutionary origins and potential extinction of magical creatures. Unlike many vampires, he maintains a strict moral code and frequently associates with non-vampires. He is highly protective and quick to anger when his loved ones are threatened.

Ysabeau is Matthew's elegant vampire mother and the matriarch of the de Clermont family. She holds a deep hatred for witches following the death of her husband during World War II. Fiercely protective of her son, she commands significant respect and authority within her household.

Marcus is a skilled healer and scientist who assists Matthew with DNA research. Matthew turned him into a vampire during the American Revolutionary War. He possesses a bright, cheerful demeanor but takes his ethical responsibilities as a vampire seriously.

Knox is a powerful wizard and a high-ranking member of the Congregation. He believes witches are the superior magical species and demands that Ashmole 782 be returned exclusively to them. He views Diana's association with a vampire as a betrayal of her kind.

Satu is a formidable witch with platinum-blonde hair and blue eyes. She works closely with vampire members of the Congregation to extract information about the missing manuscript by any means necessary.

Gerbert is an ancient vampire and a ruthless member of the Congregation. He frequently plots against the de Clermont family and utilizes other creatures to achieve his political goals.

Sarah is Diana's outspoken, fiercely protective aunt. She raised Diana in Madison, New York, following the death of Diana's parents. A skilled witch who relies on traditional spells and potions, she distrusts vampires and daemons entirely.

Emily, affectionately known as Em, is Sarah's life partner. She is a gentle, soft-spoken witch with a powerful sixth sense and an aptitude for visions. She provides a calming counterpoint to Sarah's fiery personality.

Hamish is a daemon who works as a highly successful financial analyst. He met Matthew at Oxford decades ago, forming a rare cross-species friendship based on mutual intellectual respect. He is observant and often provides Matthew with grounded advice.

Miriam is a practical, serious vampire who works alongside Marcus in Matthew's genetics lab. She is highly critical of Matthew's interest in a witch, fearing the consequences of breaking the long-standing inter-species covenant.

Agatha is a stylish, Australian daemon who serves as a representative on the Congregation. She hopes the missing Ashmole manuscript will explain the true purpose and origins of daemons.

Nathaniel is Agatha's son and a self-assured daemon. He is highly protective of his pregnant wife and willing to challenge traditional species boundaries to secure a safe future for his family.

Sophie is a gentle daemon who was born to a family of witches. She experiences powerful visionary dreams and is currently pregnant with a child she believes will be a witch, violating strict segregation rules.

Gillian is a visiting American scholar and witch at Oxford. She heavily prioritizes species loyalty and feels insulted by Diana's refusal to practice magic or associate with the coven.

Baldwin is Matthew's older stepbrother and the strategic head of the de Clermont family. Created during Roman times, he prioritizes the safety of his vampire relatives and deeply resents Matthew's association with a witch.

Juliette is a beautiful, unstable vampire from Matthew's past in New Orleans. Groomed by Gerbert specifically to infiltrate Matthew's life, she harbors an intense, dangerous obsession.

Marthe is the stout, observant vampire housekeeper and cook at the de Clermont estate. She speaks Occitan and provides a warm, maternal presence in the fortress-like home.

Rebecca is Diana's deceased mother. A talented witch with a rebellious streak, she took drastic, secret measures to protect her daughter's magical potential before traveling to Africa, where she died.

Stephen is Diana's deceased father. He was a powerful wizard who deeply mistrusted Peter Knox and left behind magical safeguards to protect his family's legacy.