[Ibrîniðilpathânezel]

For the main villain, I'd say the Ring. There are really too many people who contributed significantly to the success of the quest to say that there is one hero or central character, IMHO, but for myself (after more than 45 years of being a fan and student of the book), I think of Frodo, Gandalf, and Aragorn as a heroic triad (which is pretty well summed up by Aragorn at his coronation: "By the labour and valour of many I have come into my inheritance. In token of this I would have the Ring-bearer bring the crown to me, and let Mithrandir set it upon my head, if he will; for he has been the mover of all that has been accomplished, and this is his victory.")