Fyr certainly has to be amoung the elite few if not the most powerful himself
I betcha Aryon is no weakling either especially if the TElvanni under his reign have established a strong precense in morrowind given the events of obilivion
I agree. Fyr and Aryon are probably two of the, if not the most, powerful people in Tamriel. Fyr's been alive for close to Four thousand Years (if memory serves me correctly) and is probably the most powerful Telvanni Mage-Lord. Aryon, on the other hand, appears to be just as powerful as Fyr. After all, he dismissed two Magical Items as if they were nothing to him. Saying that he didn't need them anymore. (And let's keep in mind that one of these could summon a trio of Atronachs, where as the other could control most of the people in Vvardenfell, Gameplay wise.)
Mind you, just as many others have said; The Champion of Cyrodiil, and the Nerevarine are very powerul too. The Nerevarine did, of course, kill two Gods (Dagoth Ur, Almalexia) and prett much beat the crap out of Hircine. He also, quite possibly, gutted Vivec. The Champion, on the other hand, fought huis way through hordes of Daedra, defeated Umaril the Unfeatherd forever, and took up the mantle of the Madgod, himself.
Hmmm. I wonder what would happen if the Champion and the Nerevarine has a showdown...
Battle Royale!