What is the theme in Running with the Demon by Terry Brooks?

Sense of family is a theme in this book. Nest Freemark is raised by her grandmother, Evelyn Freemark, and grandfather, Old Bob Freemark, after her mother, Caitlin, kills herself. The women of the family have always been in service to the Word as guardians of the Sinnissippi park. Nest is continuing the family tradition of guarding the people of Hopewell from the feeders in the parks. Nest is close to her grandparents, but she has no idea who her father is. Her grandmother refuses to talk about it, so Nest is left to dream about the kind of man her father might be. She hopes that John Ross, a Knight of the Word, could be her father; however, she is devastated to learn the demon is her actual father.