The Powers of the Istari

[Belegorn]

Originally Posted by denethorthefirst

For all we know there could be some Maiar that were more powerful than some Valar, but because of their character and interests they ended up as "helpers" under a Vala that was more powerful. It is quite possible for example that Sauron was more powerful than some of the lesser Valar like Nessa or Vana, but because of his character and his love for construction he became a "helper" (Maia) of Aule, who was also more powerful than him.

I doubt this. The closest I've seen to any Maia even being equal to a Vala is that they are less than equal to them. The Silmarillion states "the Valar drew unto them many companions, some less, some well nigh as great as themselves" [Ainulindalë, p. 12] Of the 13 Valar "Nine were of chief power and reverence... surpassing beyond compare all others, whether of the Valar and the Maiar, or of any other order that Ilúvatar has sent into Eä." [Valaquenta, p.23] These were Melkor, Manwë, Varda, Ulmo, Yavanna, Aulë, Mandos, Nienna, and Oromë. The Maiar are known as the companions of the Valar, but of "a less degree". Some Maiar may come close to matching the Valar, but in this case only those six Valar who were not included among the chiefs which would include Tulkas, Lórien, Estë, Vairë, Vána and Nessa.

I'd say that since none come close to the chief who are "surpassing beyond compare all others" then the reference to some of the Maiar being "well nigh as great as themselves" has to be in reference to the lesser Valar. Therefore there would be Maiar who come close in comparison to the Valar, but only the lesser Valar [Tulkas, Lórien, Estë, Vairë, Vána and Nessa], but so far as I can tell none are mightier than any Vala.