First off, I realize that the HISHE (How It Should Have Ended) YouTube channel deals in movies, not books, and that the Lord of the Rings movies took quite a few liberties with the source material (for those who have not seen the HISHE vid, you can watch it here). That being said, some people believed that the short, animated comic brought up a glaring weak spot in Tolkien’s original work. Namely, if the Eagles participated in the Battle at the Black Gate, why did they not help out before? And, since they didn’t help before, did Tolkien bring them in at the last minute just to even the odds out and buy Frodo and Sam more time? The Nazgul’s mounts were pretty much unstoppable. Aaragorn did not have any aerial forces of his own, and arrows were shown to be pretty much useless. Even worse, most Men simply quaked under the Shadow of the Nazgul riding them. So, even though it would have been a hopeless battle simply out of sheer numbers before, the Nazgul and their pets would have crushed the opposition incredibly quickly had the Eagles not shown up. Which is why many people have asked the following question:
Is this a case of Deus ex Machina?
The answer to that question completely depends on if you are limiting yourself in scope to The Lord of the Rings novel alone, or Tolkien’s world at large. What I can definitely tell you is that this was not a lazy writing tactic by Tolkien.
If you are looking just within the covers of The Lord of the Rings, you won’t find much of a direct explanation – at least, not entirely. As to why the Eagles are not participating from the very beginning, it’s very similar to the answer the about giving Tom Bombadil the Ring during the Council of Elrond. Bombadil isn’t overly concerned with the Ring or what goes on outside his land. He is a good being in the sense that to those he meets he is kind, generous, and hospitable. But he very much keeps to himself (something both Tolkien and CS Lewis felt the world could use a good deal more of). He is not terribly invested in things that do not concern his immediate affairs; and the Eagles are even less reliable.
We get great insight into the mindset and worldview of the Eagles in another book. Not the Silmarillion (though I could make an argument about the Eagles relationship with Manwë, and Gandalf reminding us that there are forces for Good and not just Evil) that wasn’t published until after Tolkien’s death, but the book that started it all for his readers: The Hobbit. And since The Lord of the Rings is a direct sequel to The Hobbit, everything presented in it certainly should be considered when evaluating if there was any previous content that explains something that happened in its successor. Let’s take a look at the text.
Eagles are not kindly birds. Some are cowardly and cruel. But the ancient race of the northern mountains were the greatest of all birds; they were proud and strong and noble-hearted. They did not love goblins, or fear them. When they took any notice of them at all (which was seldom, for they did not eat such creatures ), they swooped on them and drove them shrieking back to their caves, and stopped whatever wickedness they were doing. The goblins hated the eagles and feared them, but could not reach their lofty seats, or drive them from the mountains…
…The Lord of the Eagles would not take them anywhere near where men lived. “They would shoot at us with their great bows of yew,”he said, “for they would think we were after their sheep. And at other times they would be right. No! we are glad to cheat the goblins of their sport, and glad to repay our thanks to you, but we will not risk ourselves for dwarves in the southward plains.” “Very well,”said Gandalf. “Take us where and as far as you will! We are already deeply obliged to you. But in the meantime we are famished with hunger.”
As you can see, a big emphasis is made on the Eagles being, well, eagles. They even steal from Men. Of course, they don’t consider it stealing. The sheep are their natural prey and, as eagles, they don’t recognize human laws of property – and even if they did, it would be highly unlikely they would recognize any pertaining to the ownership of animals. They are noble, in a fashion, but they are not self-sacrificial. They’ll leave the Dwarves to face danger over risking themselves for them. Bombadil’s goodness is limited by minding his own affairs. But the Eagles goodness is limited by their very being. The Eagles are still animals, not creatures of a human-like spirit in an animal body. They may have a wit that can be compared to sentient beings, but not a heart. They still think with the same goals and passions of an animal, just a very intelligent one. They “rescued” the Dwarves not so much out of compassion for creatures about to die, but rather to spoil the sport of their natural enemies, the Wargs.
Gandalf, who has no patience with foolish arrogance with Hobbits, Men, and Dwarves, is shown having to be very cautious, placating, even flattering, to get the Eagles to take them even as far as Beorn’s lands, and that’s nowhere near as long of a trek as Mordor. At the same time, the Eagles do attempt to show some hospitality, but the text makes it quite clear that this is done primarily out of gratitude to Gandalf treating the Lord of the Eagles when he had been wounded by an arrow. So, it appears a lot of the helpfulness is because they feel indebted to Gandalf personally. Once again, it’s not altruism that is their motivation.
Now it’s pretty easy to see why HISHE’s scenario wouldn’t work. But that leaves one more question – why did they come at the end?
This answer only takes a little bit of thought and zero stretching to come up with a possible answer. The Eagles were Lords of the sky, unchallenged in their aerial dominance. We also know they kept aware of news outside of their lands. The Nazgul’s flying mounts, once they appeared, challenged that dominance. And, obviously, they knew of the War, and had even witnessed Saruman’s treachery when Gandalf needed rescuing.
Therefore, I believe the answer is that the Eagles came to ensure their continued dominance of the skies. Not only did the Nazgul directly threaten this now, but Mordor’s might was also unveiled at the Battle of Pelanor fields. The Eagles knew that Aaragorn’s forces would fail without aid, and if that happened, they too would eventually fall to Mordor. In other words, the Eagles were reluctant allies that helped for their own benefit once they realized they must aid or perish.
You might think I’m being overly harsh on them. Actually, if we were able to have a conversation with them, I believe they’d tell you the exact same thing. It’s not a blemish on their character. They are Wild; they are animals. Animals don’t go around fighting evil for the sake of Goodness. They fight whatever they are confronted with that threatens them. The Eagles are no less heroic than a dog that only attacks a robber to save his family/pack instead of prowling at night seeking to stop evil its tracks in the name of Justice. In this case, they did seek out the evil and confront it – but, only because their intelligence allowed them to see that the threat to their own concerns than that of a regular animal. But their motivation was still the same as it had always been – to protect their own interests first and foremost.
And that’s my explanation. But, to answer the question about Tolkien using Deus ex Machina, I’ll say this:
If it was, then it was Deus ex Machina done right. It wasn’t done out of laziness of the writer. The perception has more to do with forgetting content from the previous novel by lazy critics.