In a world where civilization is spread thin as it is, an assassin seems useless. Law's gone, you could just attack them, except for in Stormhold. Even if you want to kill someone in Stormhold, you could just lure them to a camp and get them killed "by your actions". I wouldn't think an assassin would be needed at all. Maybe a pathfinder/scout, but after you reach Stormhold, even that's pretty much useless. A better choice would be a warrior, or a hunter, or a mage, seeing as (as far as I know) there's no mages yet.