Balrog and The One Ring

[Faramir Jones]

In terms of the ability of Gandalf to fight Sauron in person wearing the One Ring, Tolkien had this to say, in Letter 245 of 25th June 1963 to Rhona Beare:

Of the others only Gandalf might be expected to master him [Sauron] - being a emissary of the Powers [Valar] and a creature of the same order [Maiar], an immortal spirit taking a visible physical form.

Tolkien then discussed if Elrond or Galadriel could have wielded the Ring and supplanted Sauron:

they would have built up an empire with great and absolutely subservient generals and armies and engines of war, until they could challenge Sauron and destroy him by force. Confrontation of Sauron alone, unaided, self to self was not contemplated. One can imagine the scene in which Gandalf, say, was placed in such a position. It would be a delicate balance. On one side the true allegiance of the Ring to Sauron; on the other superior strength because Sauron was not actually in posession, and perhaps also because he was weakened by long corruption and expenditure of will in dominating inferiors. (My emphasis)

Originally Posted by Marwhini

Why would the Balrog WANT to fight Sauron (especially given their loyalty and allegiance to Morgoth - see above)?MB

His allegiance was given to Morgoth, not Sauron; so he might not have automatically given allegiance to the latter. Also, it's possible that he might have fought Sauron on the grounds that he had gone 'soft'. Tolkien made it clear in Morgoth's Ring that Morgoth wanted to destroy every living thing on Arda, including his own creatures such as Orcs, once the Elves and Men were destroyed. Sauron, by comparison, didn't mind things living, as long as they acknowledged his supremacy.