Emily Mather is Sarah Bishop's partner. Emily is a witch, can fly for short distances and can sometimes see the future. Emily is fine-boned.
Emily ("Em") met Diana Bishop's mother, Rebecca Bishop, when they were both high-school students working on an archaeology dig. Em attended Vassar, and then reconnected with her friend Rebecca in Cambridge, Massachusetts when Em became a children's librarian. After Diana's parents died, Em started working at a school near Diana's house. Diana's aunt, Sarah Bishop, became partners with Em. They raised Diana together thereafter.
A Discovery of WitchesEdit
Em coaches Diana when Diana is practicing her timewalking, telling her that "magic is in the heart as well as the mind." Em and Sarah go to Sept-Tours, the home of Diana's mother-in-law, Ysabeau.
Shadow of NightEdit
Emily is surprised that Ysabeau seems to be searching through all of the books in her home library for something. She recognizes the danger that Diana is in due to Diana's relationship with Matthew, and the possibility that timewalking in the past may change the present.
The Book of LifeEdit
In the initially released USA Today excerpt, Philippe as a ghost is chatting with Emily as a ghost at Sept-Tours. He tells her that endings, beginnings, and change are ahead. Emily tells him that Diana has always resisted change. Philippe says that it's because Diana is afraid of what she must become.