Characteristics
Tom Bombadil is a spry fellow, with a quick, playful wit. He speaks in a rhyming whimsical way: "Hey dol! merry dol! ring a dong dillo! Ring a dong! hop along! fal lal the willow! Tom Bom, jolly Tom, Tom Bombadillo!" He has a jolly, carefree attitude, and very little seems to concern him. He sometimes refers to himself in the third person, as if simultaneously weaving his own epic narrative, even as he lives it.
He certainly does not seem concerned about the One Ring, even though he seems to know at least as much as the hobbits about its connections and possible consequences. Indeed, this aspect of his personality seems quite perplexing: the discussions of those at the Council of Elrond at Rivendell, and especially those of Gandalf, seem to indicate that Bombadil would not be immune to the actions of a rejuvenated Sauron; however, he seems to be wholly unconcerned with this fact and immune to the power of the Ring. In fact, the closest thing to an adversary Bombadil has, in the loosest sense of that word, is possibly Old Man Willow, who occupies and holds dominion over the trees in miles of Tom's "country"; although Bombadil does seem to demonstrate at least some control over even him.
Tom Bombadil's origins in the cosmology of Middle-earth were left vague by Tolkien. He calls himself the "Eldest" and the "Master". He claims to remember "the first raindrop and the first acorn", and "knew the dark under the stars when it was fearless — before the Dark Lord came from Outside." He does not neatly fit into the categories of beings Tolkien created. Speculative ideas about his true nature range from one of the Ainur, angelic beings (who came after the Dark Lord and shaped the earth), to God, who is called Eru Ilúvatar and "the One" in Tolkien's legendarium although Tolkien rejected the notion that Bombadil is God. This is however reinforced when Frodo asks Goldberry just who Tom Bombadil is, and she responds by simply saying "He is" (which Tolkien was careful to distinguish from the Biblical "I Am that I Am".)
At the Council of Elrond, Galdor suggests that Bombadil would be unable to withstand a siege by Sauron "unless such power is in the earth itself", implying that the character may be a manifestation of Middle-earth's inherent properties. This connection explains Bombadil's seeming obliviousness to the transient concerns of mortals, as evidenced in Gandalf's concern that Tom would not understand the importance of the Ring and would lose it if entrusted with it.
In reference to Bombadil, Tolkien himself said that some things should remain mysterious in any narrative, "especially if an explanation actually exists". Tom Bombadil is not the only being whose nature is unexplained. While passing Caradhras in Book II of The Fellowship of the Ring Aragorn mentions beings more ancient even than Sauron. In Book III of The Two Towers, when describing his fall in the pits of Moria, Gandalf mentions dark creatures who gnaw the world. In addition, Tolkien placed the fate of the Entwives in this enigmatic category, as well as the Cats of Queen Berúthiel.
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