Deborah Armstrong is a cruel and selfish sixteen-year old girl who resides in New Salem with her family. Deborah is the only child of Mr. Armstrong and Grace Armstrong. After the arrival of Cassie Blake, Deborah is initially hateful toward Cassie, however she later becomes an unsuspected ally of Cassie, after the discovery of Cassie’s exceedingly powerful magic. Throughout the series, Deborah is the best friend of the equally mean Faye Chamberlain. Despite her attitude, she respects those who stand up to her and likes Cassie because she has a hidden strength. She is compared to the goddess of hunting Artemis. Deborah's working crystal is Citrine.