A powerful weaver and witch, Stephen Addison Proctor was the father of Diana Bishop and husband of Rebecca Bishop and a powerful time traveler in his own right. Despite his abilities, he was killed during a trip to Nigeria with his Rebecca.
Stephen studied anthropology at Harvard and taught at Wellesley. He was a powerful wizard from a distinguished magical lineage, but he didn't flaunt his power. Stephen usually was easy-going, stubborn, and other witches thought he kept secrets. He died on a trip to Nigeria with his wife, Rebecca Bishop.
Stephen, unlike other Witches, held many secrets that he did not share with his fellow witches, with some such as Peter Knox attempting to find out his many secrets by any means necessary in his eyes, leading to Stephen's and his wife's death at the hands of Peter. His greatest secret was his identity as one of the few Weavers left in the world. Due to the rarity of Weavers he was self taught in the talent of spell making leading to him never learning the formal nine knots, with his spells being more patched together rather than weaved.
Unlike his fellow witches, Stephen was not prejudiced in any way toward vampires or daemons. He believed that in order for their races to continue and thrive, that they must work together. He was known to be leveled headed, fair, and openminded. He never abused his powers or flaunted his or his family's status over others. This earned him not only respect and friendships from members from the three magical races, but also jealousy from some witches, especially from Knox who viewed Stephen as a threat to his power.
It is heavily implied that Stephen was aware of families such as Sophia's, a race born from a different race, but didn't reveal his discovery as he knew the Congregation would have those children either killed or taken from their parents. It is also implied that he helped several go into hiding. Most of all Stephen was shown, throughout both the book and tv series, to be a master planner. This is shown with him leaving clues for Diana to find at the exact times she needed them, weaving the spell that bound Diana's powers to break only when she met her protector and soulmate Mathew, giving Diana the tools she needed to find the right teachers during the right time period, and putting various obstacles that continued to hinder Knox even decades after his death.
A Discovery of Witches
Diana discovers that Stephen and Rebecca spellbound her to protect her from drawing other witches' attention to her. She also discovers that Stephen could magically travel in time, and that he bewitched Ashmole 782 so that only Diana could obtain it from the Bodleian Library at Oxford.
In a letter to Diana Bishop it was revealed that Diana's immense power as a child was being sensed by the Witches of the Congregation. Stephen and his wife Rebecca Bishop discovered the Congregation was in search of this incredible power leading to begin the process of spell binding. Diana was bound slowly over several months as her parents did not wish to frighten her in a binding ritual. However, Peter Knox found the source of the magic he felt was originating from the Bishop family and appeared in Madison, New York. Now with no time left, Rebecca and Stephen decided to hide Diana's powers for good, to lie in wait for the Shadow Prince Rebecca saw in her visions, Matthew Clairmont, to be able to protect her.
Peter Knox, much to her parents' distrust, tested Diana's abilities but thanks to the binding her abilities were sealed and undetectable to Peter. After the test, Peter and Stephen left to the kitchen where Diana said she remembered them arguing about something while Rebecca sat with Diana in the living room. Stephen, knowing the Congregation and Peter, knew the power was coming from the house, left a trail of fake bread crumbs away from Diana and towards himself leading to the Congregation believing he was the source of the power they all sensed. Stephen and Rebecca left for Nigeria knowing they were being followed by Peter Knox and knowing their deaths were in the near future. They both fled to Africa in order to draw attention away from Diana, with Stephen and Rebecca sacrificing their lives to keep Diana safe.
Shadow of Night
Diana and Matthew meet up with Stephen when they are all time walking in 1591 London. Stephen helps Diana feel more relaxed about her magic and life, and more open to the possibilities.
The Book of Life
Stephen's spirit appeared to Diana Bishop after she successfully summoned Witch Water in the Bishop home in Madison, NY. He congratulated her on her magic hugging her from behind exclaiming "Well done, Peanut." his nickname for Diana as a child.
Stephen's spirit also appeared to Diana in Chelm, Poland while she battled Peter Knox in Benjamin Fuchs' hide out. Diana wove the strongest spell in the series so far, apart from the Tenth Knot. The spell summoned the spirits of all the Weavers to have ever lived, including Stephen's, to drain away Peter Knox's life force by reverse weaving his soul into nothingness, effectively destroying him in body, mind and soul.