From what I've seen, the toolset lets you edit everything BUT the player character itself. So the official answer would be 'no'. There might well be trainers and the like around which do let you edit your characters, or let you create new classesof your own, in which case I'm sure the game
will recognise the Blackguard class. I haven't felt the need to go searching for those yet, though, so if they can be found, don't ask me where
