Ancalagon
Great dragon of Morgoth. Ancalagon breathed very dangerous fire. This fire, however, could not destroy the Third Age's Ring of Power. Ancalagon, however, lived in the First Age. He fought only the War of Wrath, and was the last defense of his master's tower, Angband. In the time of greatest need, Morgoth sent Ancalagon forth to catch the attacking valar by surprise. They retreated, but then returned with Eagles. The three forces fought airborne for a full 24 hours while below, Elves, Edain, Dwarves, Ents, Druedain, Easterlings, and probably Lossoth fought orcs, wicked men, and maybe even Trolls. Finally, Earendil the Elf killed Ancalagon. His body crushed the towers of Thangordrim. Eventually, when the host of the Valar's numbers grew too great, and the Elves, Dwarves, Edain, Ents, Easterlings, Druedain, and Lossoth refused to stop attacking, Morgoth surrendered.