First off the "Old lady" was awesome.
You magic is really interesting, and I feel like you handed the learning curve well.
The blocking in the fight could be a little clearer. The fire in the room came out of nowhere to me, as I was like he just drained the fire. On further reflection I realized that Alduin was stalling by draining the torches but that didn't come to me until I though back on the whole fight.
Some minor points that I feel obligated to mention.
Throwing a knife. I own throwing knives and while i cant hit anything with them I now people who can pick them up and hit the target in a few tries. That being said, it is hard to hit a moving target with significant penetration with an balanced knife at an unknown distance especial under pressure. Just bear in mind that throw would be very hard to make. Then again it was cool so realism doesn't bother me to much on it.
Fire swords. I love these, I think they are awesome. However, fire is not a solid and has no significant mass. So a sword of fire would in fact pass through a blade rather then stop on contact with it (at least that is my understanding). But its magic so I can get on board with it . Just some food for thought.
I am interested to see what happens next.