Kettle was the name Kestrel was known by in her final years. She appeared to be an old lady of Buck, first travelling along a group of pilgrim to Eda's shrine in the Mountains, and then later on attaching herself to Fitz on his quest to find Verity.
In truth, she had been banished from Buck for killing her twin sister Gull with her Skill. As a punishment, her Skill was locked within her. As she had used it to herself to keep young and heal fast, she still lived even if she was well over 200 years old.
After her banishment from Buck, she had travelled far and found a lot of information of the White Prophet and their prophesies. She was travelling to the Mountain Kingdom to find the White Prophet when she met Fitz. Kettle helped Starling save Fitz from Burl in Moonseye. She insisted coming along to find Verity, even if she had trouble keeping up with others. She trained Fitz in the use of the Stone Game as a meditation tool and gave him some training in the Skill. After she revealed her past to Verity and Kettricken in the Stone quarry, her unusual knowledge of all things related to Skill became understandable. Fitz was able to release her from her Skill-prison by making her forgive herself and she helped Verity to create Verity-as-Dragon.