When Sauron Wears the Ring (FOTR)

[Stacy]

I see Bombadil as a sort of a nature spirit. Tolkien said in one of his letters -

"Do you think Tom Bombadil, the spirit of the (vanishing) Oxford and Berkshire countryside, could be made into the hero of a story?"
The Letters of J.R.R. Tolkien, No 19, dated 1937

It is possible for him to be of an order that Tolkien just did not describe.