Illistyl was born in Shadowdale. She first met the Knights while they were searching for a weretiger that had killed the thief Alura Durshavin. Doust Sulwood, at that time the Lord of Shadowdale, allowed her to live in the Twisted Tower of Ashaba after her parents died fighting with Zhent forces.
She was tutored in the magic arts by Jhessail Silventree and when her teacher became pregnant, Illistyl replaced her among the Knights. After Jhessail's child was born, Illistyl quickly stepped down and acted as baby-sitter for the young one while the mother returned to fight. She later took care of the magical needs of the Dalesfolk in place of the deceased Sylune.