*Scratches head* I was not expecting to have to dawdle too much on what's what - it's a free form, hack n slash RP that you're getting thrown into head first. 

Well I be reckoning that everyone likes magic, so I say: go wild. The "barbarians" are an undefined force of attackers, you're all supposed to be newly arrived soldiers at the castle with no-to-little experience of what's been happening in the area. I was hoping that the players collectively would give shape and life to our adversaries. All we know at the moment is that they're tall, strong and full of murderous intent. 

To make for a better narrative though, I always go by the rule "What I can do, they can do better", that way your character avoids being God whilst at the same time gets to celebrate his/her victories more over an otherwise superior enemy.