Im sure someone will explain why it isnt so. Im not really lore expert...
Anyway... I recently saw youtube video about most powerful Daedric Princes. The video claimed that Sheogorath is the most powerful.
The logic behind this claim was that he is able to manifest upon Nirn like no other Prince can do.
Also we know from the Oblivion: Shivering Isles that Sheogorath used to be Daedric Prince of Order, Jyggalag. Who grew so powerful that rest of the Deadric Princes banded together against him and cursed him with madness.
Personally i think that the rest of Princes only did it because it was convinient to do so. Although i must say i dont remember the events of Shivering Isles that good anymore.
So, when Jyggie was cursed, he would presumably lose control much of the realm which he controlled with his Order-thingy? Leaving Sheogorath with his Shivering Isles.
This would explain how Sheo is able to manifest more freely upon Nirn compared to other Princes?
Right? Its sound logic i think.
Anyways. About the video of most powerful Daedric Prince. I think its Boethia. Didnt Boethia defeat and eat the elven god Trinimac. Then *** out him as Malacath thus creating whole Orsimer race.
I dont know if any other deity has accomplished victory over other? I doubt they agreed to honourable duel either.