Lydia van Bredevoort was Vilgefortz's assistant and personal secretary, a sorceress, and a painter. She was a woman with a very strange face and very nice, expressive eyes. The lower part of her face was actually an illusion. Four years prior the events in Blood of Elves, Lydia, at Vilgefortz's insistence, had taken part in some experiments conducted on a mysterious artefact discovered in a necropolis. It turned out to be cursed and although it "activated" only the one time, three of the five mages who participated where killed on the spot. A fourth lost his eyes, his hands and went mad. Lydia escaped with burns, a mangled jaw, and throat and larynx mutations that stubbornly resisted all attempts at regeneration. She was left with telepathy as her only form of communication.
She was also hopelessly in love with Vilgefortz but too proud to admit it and he in turn was too principled to take her as his lover because he did not actually love her, though it was suggested. This situation, strange though it was, seemed to suit them both.
She died, likely by her own hand and at Vilgefortz's order, during the coup on Thanedd Island. When she died, the illusion that had hidden the monstrous result of the failed experiment dissipated and her true face was revealed, much to the horror of the witnesses.