This book was similar to the whole Star Wars Luke Skywalker/Darth Vader story, except it's a fantasy novel. I seem to recall that it was more of a 'young adult' level book.
Details I remember:
- Young adult level
- Written on or before the late 80's
- Heavy Norse influence in names, locations, environment
- Main character finds out that the evil scary warlord? warlock? he'd heard about is his father
- Father turns out to be NOT evil in the end
- Possibly written by female author
- Possibly studies magic with a wizard when he finds he can do magic
- Wizard possibly turns out to be a bad guy
- Upon meeting his father (near the end?) he runs off and becomes a hermit for a time (few years?)