Part of the difficulty is that you really can do whatever you want. We have had quite a bit of different types in the first SpellMaster. The basic restriction is that he has to come from the game world somewhere. So he can't be an alien, time-traveller, etc. - but he can be a peasant, a priest, a knight, anything really. I wouldn't want him to be a king or higher noble, because he couldn't possibly keep his magic a secret if he's so exposed.