Diana is a 33-year-old history of science professor and a uniquely powerful witch known as a weaver. Her ability to see and manipulate the threads of time allows her to travel to the Elizabethan era, though she struggles to adapt to the restrictive gender roles of the 16th century. Determined and independent, she seeks a tutor to help her master her unpredictable magic.

Matthew is a centuries-old vampire who operates as an active spy for Queen Elizabeth I. While he attempts to protect Diana from the dangerous politics of the 16th century, his methods often clash with her independence. He carries immense guilt from his human past and constantly battles a hereditary condition called blood rage, which makes him dangerously possessive.

Philippe is Matthew's formidable vampire stepfather and the patriarch of the de Clermont family. Though deceased in the 21st century, he is fully alive and commands massive authority in 1590. He practices ancient Greek religion and initially views Diana with skepticism, pushing her through rigorous tests before officially accepting her into his lineage.

Kit is a daemon and renowned English playwright who works as an intelligence agent alongside Matthew. He is intensely attached to Matthew and harbors a deep prejudice against witches. His jealousy over Matthew's marriage to Diana drives him to spread dangerous rumors and actively scheme against her safety in London.

Peter Knox is a leading figure among the witches in the Congregation. In the 21st century, he continues his ruthless hunt for Diana and the Ashmole manuscript, utilizing spies and historical archives to track the de Clermont family.

Gallowglass is Matthew's Norse-mercenary vampire nephew. With his imposing physical stature and quiet vigilance, he serves as a highly effective bodyguard for Diana throughout her time in the 16th century. He harbors a deep, enduring loyalty to his family and operates with a pragmatic approach to violence.

Mary is the Countess of Pembroke and a dedicated alchemist. She uses her high social standing to bypass the restrictions typically placed on Elizabethan women, running her own laboratory and educating her female servants. She becomes a vital ally to Diana, offering both genuine friendship and scientific collaboration.

Goody Alsop is an elderly, lower-class witch and the last remaining weaver in Britain. She understands the unique mechanics of creating spells from magical threads and takes on the responsibility of mentoring Diana. She represents an ancient line of magical knowledge that is actively hunted by others.

Annie is a 14-year-old orphaned teen witch rescued from the streets of London. She is taken in by Diana and Matthew as a household servant but is quickly treated like an adopted daughter, receiving an education and a safe home.

Jack is a traumatized human orphan who survives by stealing on the streets. He is brought into the de Clermont household, where he bonds deeply with Matthew, who helps soothe his severe nightmares.

Father Hubbard acts as the vampire king of London's supernatural creatures. He maintains a massive flock of vampires, witches, and daemons who trade their allegiance and blood for his formidable protection from the Congregation.

Ysabeau is Matthew's vampire mother and Philippe's wife. In the 21st century, she aids in protecting Diana's family and unraveling the mysteries left behind by her husband in the past.

Marcus is a vampire sired by Matthew during the Revolutionary War. In the present day, he works to reform creature society by convening a cross-species Conventicle, while also uncovering artifacts left behind by Matthew and Diana in the 16th century.

George is a human poet and member of the prestigious School of Night. He is one of Matthew's mortal friends in Elizabethan England and treats Diana with genuine kindness and curiosity, helping her navigate the local apothecaries.

Walter is a famous human explorer, writer, and central figure in the School of Night. He values rational thought and defends Diana's presence among their secretive scholarly group, believing they owe Matthew their assistance.

Thomas is a brilliant daemon scientist and mathematician belonging to the School of Night. He is a forward-thinking astronomer whose inventions, including an early spyglass, are quietly aided by Diana's historical knowledge.

Henry is the Earl of Northumberland, a wealthy human nobleman and patron of the School of Night. He is a pragmatic intellectual who readily accepts Diana's unconventional background and aids Matthew's endeavors.

Sarah is Diana's aunt who raised her after her parents died. A practical, traditional witch in the 21st century, she helps guard the Bishop family secrets while Diana is in the past, eventually taking refuge with the de Clermonts.

Emily is Sarah Bishop's partner and a gentle witch who helped raise Diana. She provides emotional support and historical insight to the modern-day allies gathered at Sept-Tours.

Gerbert is a powerful vampire who sits on the Congregation. He serves as an ancient rival to the de Clermont family, gathering intelligence in the modern era to use against them.

Rudolf is the Holy Roman Emperor residing in Prague, an obsessive collector of occult artifacts and unusual people. He aggressively courts Diana, seeking to add her to his infamous cabinet of curiosities alongside the Ashmole manuscript.

Edward Kelley is a volatile alchemist residing in Prague who possesses the coveted Ashmole 782 manuscript. His mind is dangerously connected to the dark magic of the book, causing him to act erratically when anyone attempts to take it.

John Dee is Queen Elizabeth's royal astrologer and a renowned scholar. He possessed the highly sought-after Ashmole manuscript before it was stolen by his former assistant and taken to the Holy Roman Empire.

Elizabeth is the formidable monarch of 1590s England. She commands Matthew as her personal spy and expects complete loyalty, viewing his sudden marriage and secretive activities with extreme suspicion.

Stephen is Diana's deceased father, a powerful witch and timewalker. He encounters Diana during her time in the past, offering her crucial guidance regarding her magical abilities before returning to his own era.

Benjamin is a dangerous and mysterious vampire operating in Prague who bears the mark of the Order of the Defeated Dragon. He carries the severe affliction of blood rage and draws the attention of those searching for the missing manuscript.

Louisa is Matthew's erratic vampire sister. Highly susceptible to blood rage, she views Diana as a dangerous threat to the de Clermont family lineage and violently schemes to eliminate her.

Corra is Diana's familiar, a magical firedrake that manifests as a physical embodiment of her weaving power and protective instincts. She emerges to defend Diana in moments of extreme danger.

Phoebe is an employee at a prestigious London auction house who facilitates the sale of 16th-century miniatures to Marcus. She is soon introduced to the hidden world of supernatural creatures.