Tissaia de Vries was a sorceress and a member of the Chapter of Sorcerers. She was one of the rectors at Aretuza and the author of The Poisoned Source. She was also extremely obsessive about her appearance and things in general. Tissaia was the one who took a young Yennefer of Vengerberg under her wing. It was she who fixed Yennefer's hunchback and cured her of her various afflictions. __TOC__