Board Thread:Lore Discussion/@comment-6702118-20140722142914/@comment-31431607-20180123231947

207.228.78.94 wrote: Kirkbride's fanfic fantasylands aside, it's tough to say who would win. It appears that Alduin can't truly die until his destiny is fulfilled, so Dagon may be at a disadvantage in that right, however; I think that a one on one fight between the two would be quite deadly. There's a tale where Alduin had a very long and bloody fight with Shor but after a long while Shor won.

So I'd say Alduin is a bit upper on the scale than Mehrunes.