Isobel is found in Farglow.
Background
She is part of the plot quest The Farglow Connection, she teaches you the Mindread skill. She can be found conversing with Sonja or Gawain.
A conversation between Isobel and Gawain mentions sightings of the Black Ring.
Mindreading
"Hahaha! Nice try, but you can get out of my head now. Not even Morgana can read my mind!"