Jet's sister, known for her initially reserved and cool demeanor, whose own experience of profound love challenges her emotional barriers. She is an essential figure in navigating familial responsibilities and legacies.

Raised by Jet and Franny, she is a director at the Owens Library and reluctant to use her bloodline magic. Her practical nature comes from her aunts, and she experiences growth through personal relationships and family duties.

Sally’s sister who works in genetics at MIT, Gillian is admired for her beauty and charm. She is eager to further explore her magical abilities and manages a delicate balance between her scientific interests and personal life.

Sally’s responsible and intelligent elder daughter studying emergency medicine, who manages family obligations adeptly. She navigates personal relationships while upholding family traditions and duties.

Sally’s curious and sensitive younger daughter, intent on understanding her magical heritage. Her friendships and personal relationships guide her development and choices as she matures.

Franny and Jet’s brother, a former musician known for his profound love and ability to locate lost things. His life abroad and eventual involvement with family matters highlight differing approaches to magic and personal connections.

Ian, a former professor and writer passionate about magic who forms a personal connection through shared magical interests. Margaret is his mother, knowledgeable in the Nameless Art and instrumental in teaching others about non-bloodline magic.

Known as Bad Tom, he is skilled in hexes and poisons and is characterized by his left-handed magic practices and contentious relationship with the Owens family.

A childhood friend of Kylie, known for his height and athleticism, whose relationship with her takes a significant turn as the story develops.

A fierce attorney for the Owens family, known for her love of children's literature and personal connections within the family.

A gay librarian at the Invisible Library, previously working at the British Museum, whose past with magic intertwines with his current responsibilities, forming new personal connections along the way.

A retired high school principal characterized by his long-term secret companionship with Jet, once acting as a pivotal figure in her life during a moment of crisis.