Lydia Carlton
About
Her goal is to become a full-fledged fairy doctor, and frequently places herself in danger willingly when it comes to anything to do with problems between humans and fairies.
She appears to have some self-esteem issues, referring to her own hair as "rust-colored" and comparing herself to her mother, who was apparently a woman of considerable beauty; everyone who knew her mother before she passed away says that they don't look anything alike. Once, in an outburst, she confesses to Paul Ferman that she thinks that she isn't cute at all, and that it's part of the reason why she tries so hard to help in other ways (by working hard).
Lydia currently is considered Edgar's fiancee, a status she vehemently denies, despite Edgar's courtship of her and multiple fairies calling her that. She obtained this status when she accepted a moonstone ring (previously owned by Gwendolen, the countess of one of the past Blue Knight Earls before Edgar), which effectively meant that she accepted his proposal. The moonstone ring apparently has some protective powers of its own; it prevented Lydia's soul from being fully trapped by the fairy world in volume 6 of the novel series, as well as enabling Lydia to break Kelpie's spell on her when he tried to bring her to the fairy world by magic (to prevent her from being hurt in the crossfire between Edgar and the Prince).