Such is the nature of writing that one never knows who one is going to meet on the journey. This morning, while mowing the lawn, a young man presented himself to me. (In my head; not actually standing on our property.) A complex, somewhat difficult to understand man/boy who had just recently inherited his father's title: the thane of Cawdor.
Fleance had never met him until 'tonight' (ie the night in the opening chapter) but knew his father to be a strong and fearless warrior (evidenced in the two major battles our king has been involved in).
Personally, I'm not liking the kid but my author instincts tell me to just wait and see. This young man could turn out equally to be friend or foe.