Author: Atarah al'Norahn
Powl is one of Asne Zeramene's four Warders. He is the only one of Asne's Warders who is a Darkfriend.
After leaving the White Tower with Liandrin, Asne masks her bond to her Warders until they reach Samara, where she unmasks it, wanting to have armed men close at hand. As she feels her Warders getting closer to her, she thinks to herself that she will have to keep them concealed from the other Aes Sedai until absolutely necessary.
(Winter's Heart, Chapter 10)