Fell beasts, the flying creatures that carry the Nazgul after their black horses are lost at the Ford of Bruinnen, are some of the most fearsome creatures in all of Middle Earth. Little is known about them, other than the fact that their piercing shriek (which is actually made up of Fran Walsh screaming, over-layed with several other soundscapes in the films) has been known to stop dead the beating hearts of men. So where did these cruel beasts come from?
There are a few names by which the creatures are known, including Hell-hawks, and Wraith-birds, but the term ‘Fell Beast’ itself doesn’t refer just to these creatures alone. It is also used to describe the evil things that crawl out of Mirkwood, like the spidery descendants of Shelob. ‘Fell’ simply means ‘terrible’ or ‘full of dread’ in the old English langauge, so the name can really be applied to any of Sauron’s creatures. Interestingly, many fans of the movies think that the creatures are, themselves, called Nazgul’s, but this is not the case.
The Nazgul are the 9 ringwraiths of Sauron, and can sometimes refer to the Fell Beasts with their riders collectively, but never just to the creatures themselves. It is safe to assume then, that these beasts have been specifically bred and twisted to the dark lords will (like so many other creatures in the trilogy, including the trolls in each battle) so that they will always serve his evil purpose, and obey the 9 Ringwraiths who ride upon their backs. ‘And the Dark Lord took it, and nursed it with fell meats, until it grew beyond the measure of all other flying things, and he gave it to his servant to be his steed.’
In the Return of the King, the Fell Beasts are described as ‘a winged creature’ ‘naked, neither quill nor feather did it bear, and it’s vast pinions were as webs of hide between horned fingers, and it stank.’ There are several sightings of them across the trilogy, flying out of the Black Gates of Morannon as Sam and Frodo approach Shelob’s lair, and seen across the horizon at places like Minas Tirith, where Frodo hears the creatures' wings beat in time with the voice of the One Ring in the film, and the Dead Marshes, where the Fell Beast flies past, spying for the evil lord and reporting back their findings.
There are two known examples of the creatures being killed during the War of the Ring. The first is when Legolas manages to shoot one out of the sky as it swooped towards the Fellowship on the river, before they were separated and the fellowship was broken. The second time ever known is when Eowyn cuts the head from the horrible creature’s neck defending King Theoden in the Battle of Pelennor Fields.
It is never revealed anywhere in any of Tolkien’s writings exactly where the flying devils come from, but Tolkien did admit that their inspiration was something akin to a dinosaur, perhaps a pterodactyl. This is why the creature has a long, reptilian neck, and a thick, scaly hide, like you might expect to find on lizards and snakes. There were many disputes about how the creatures should be designed for the films, with the main visual concepts being provided by artist Jon Howe.
In the film adaptations of the trilogy, the creatures are seen to have spikes coming out of their elbow-like limbs, but this caused much controversy with a zoologist on the team who knew that this was physiologically inaccurate. It was later decided to go with the spikes anyway, to add to the fantasy element of the series, and further the dark and cruel perception of the creature. As to where in Middle Earth they sprung from, Tolkien does say ‘A creature of an older world maybe it was, whose kind, lingering in the forgotten mountains cold beneath the moon, outstayed their day, and in hideous eyrie bred this last untimely brood, apt to evil.’
What happens to them after the War of the Ring is also unknown, although it is clear that they are tied in some way to their riders, so it is thought by many Lord of the Rings fans that they perish when the Ringwraiths crumble, after the One Ring and Sauron are both destroyed. If their life force does not vanish along with their riders, then they may have been caught up in the lava that explodes from Mount Doom, or flown off somewhere to a safe refuge. However, if they have been bred in captivity and always fed by their masters, then perhaps they starve in the wild, unable to fend for themselves, and thus the breed passes out of Middle Earth forever.