User blog comment:Madman97/The Aedra Vs. The Daedra theory/@comment-7953253-20131011092738/@comment-7953253-20131013024301

I mean, I would understand a Daedric Lord's concern.

Alduin is immortal, and his destiny is to ensure the destruction of Nirn, to which he is fully capable if not for the Dragonborn's intervention.

But he's just a Dragon. If he was able to take on a much larger form than his standard form, I would understand that he would stand on equal ground with a Daedric Lord.