Given that there is reason to believe that Bethesda plans to continue with the Thalmor/Aldmeri Dominion threat and that there exists sentiment amongst the fans to destroy the Aldmeri Dominion let's see if you can find reasons for the daedric races of the Dremora, the Dark Seducers, and/or the Golden Saints to align themselves with the humans against the Aldmeri Dominion.

What we are looking for are plausible lore-friendly (or at least not lore-unfriendly) reasons why any of these races would effectively ally with the humans. Those reasons could be based on ulterior motives.

What reasons can you come up with to bring the Dremora and/or Dark Seducers and/or Golden Saints into the fight against the Aldmeri Dominion?

Well, it would be great if they did! But based on Shivering Isles dialogue especially from the Golden Saints it seems very doubtful that they care about mortals.

The reason doesn't have to be because they care about mortals. They can have ulterior motives or their own reasons which just happen to line up with that goal. Can you come up with anything for any of the three races?