Board Thread:General Discussion/@comment-11388043-20130711070950/@comment-6881629-20130717183724

I think the idea behind what Paathurnax and Arngeir say after his defeat is that when time actually does come to an end Alduin will be alowed to return so he can fulfill his prophecy as the world-eater, when (or if) Alduin returns again Akatosh probably won't stop him with a new Dragonborn.