I believe Karg follows the same track as his brother. In my opinion, it is a waste of time trying to find him. I searched forever it seemed over a couple of weeks and finally gave up. I have been told they have multiple spawn spots and it is random weather Karg or the evil brother will spawn, but once they spawn they always run the same track. I ran in to him one day by accident about halfway between the Giant statue and the South wall along the river. And he always runs somewhat fast so hard to track too. You'll just make yourself crazy trying to do Karg quests. Hope this helps some. :P