If another Daedric Prince attempted to make an attack on Tamriel, like Dagon did in Oblivion, which do you think would cause the most damage to Tamriel, or be the closest to succeeding.

As the lore stands now that couldn't happen, but assuming it could... I think Sheogorath raining cheese on cities and forcing people into insanity would be pretty awesome.

Bal and Dagon are the only ones that seem to fit the bill. If Mephala or Boethiah had that sort of ambition I could see them causing some serious terror and damage, but thats not their thing.

Molag Bal or Sheogorath if he really got pissed.....but I don't see any of the other princes having nirn conquering tendencies..