Thelfi was the wife of Logen Ninefingers, and mother to his children in the village or clan of Brynn. She was killed along with most of the village in a raid by the Shanka, while Logen was away seeking help.
In The Blade Itself, Logen encounters an icy apparition at night in Bayaz' appartment in Adua, which takes the form of Thelfi. Bayaz gets rid of it with his Art. Tolomei took his appearance when logen surprised her.