I've played Skyrim through several times (as a good guy and a bad guy) and while I'm waiting for the next game, I decided to play Oblivion. I'm really impressed with the continuity between the two games. But one thing is really bugging me; in Skyrim, Peryite is the Daedic prince of order and tasks, however in the Shivering Isles expansion of Oblivion, Jyggalag is the Daedric prince of order. What's up with that?
In Jyggalag's case, I think that "order" refers to logical deduction and determinism. This is not unreasonable considering that his Great Library contained formulae that allowed him to predict all events before it happened.
According to the Librarian, Dyus:
When the jealous Daedra cursed Jyggalag to live in opposition to all he stood for, they made him the Prince of Madness which is the opposite of logical deduction. In Shivering Isles, Dyus mentions that Sheogorath burned the library because it was the anti-thesis of his new beliefs in personal choice:
Thus, I think that the Lore strongly suggests that Jyggalag is the Daedra of Order in the sense of Logical Deduction and determinism.
Regarding Peryite, there are two main in-game sources of information on the Daedra:
Firstly, we have On Oblivion by Morias Zenon
Secondly we have The Book of Daedra
Neither of them indicate that he's a Daedra of "Order" or that "Order" is part of his sphere. Rather
Notice that in the original text, they add emphasis to the fact that he's a "Taskmaster" by capitalizing the word, but do not do the same for "ordering". This is done to illustrate what his main function is and how he's different from Jyggalag.
Thus, even if we choose to believe that Peryite is a Daedra of Order, it seems clear to me that his sphere of "Order" is distinct from that of Jyggalag's.
Of course, if this is still unacceptable, we could take the cop-out route and simply claim that Peryite took over his Lord of Order position after he became the Prince of Madness! Since Jyggalag was cursed before recorded history, this explanation isn't contradicted by any in-game manuscripts.
I think there is some confusion here. With so many Princes it is sometimes easy to forget.
Peryite, also known as the Taskmaster, is the Daedric Prince whose spheres are order and pestilence.
Whereas Jyggalag is the Daedric Prince of Order.
Peryite is more of the "balance/equality in the universe" type of Order. Jyggalag is more of the straight-lines, grey, "boring" type of Order
From what I understand(and I unfortunately have no sources for this; this is merely conjecture) Peryite is more or less Order in the form of Bureaucracy; he manages the lesser planes of Oblivion.
Jyggalag is ruler of the PLANE of Order. His whole being is dedicated to Order in and of itself, while Peryite simply uses Order as a management tool, trying to make Order from the Chaos that must stem from managing numerous planes of Oblivion.
Hope this at least gives another perspective. ^_^