One of the biggest themes in all of Tolkien’s stories is the dichotomy between good and evil. This is demonstrated not only by the narrative, in which the heroes always beat the villains, but also in the fact that nearly every being and creature in Middle Earth has an evil counterpart.
For every force of good in Tolkien's world, there is a being or creature who shares the same traits and attributes as them, but has been twisted or corrupted into something hateful by the dark forces in the world. They sometimes clash with each other, and other times simply serve as foils to show audiences the differences between what makes right and wrong.
Ravens of the Lonely Mountain vs. Crebain from Dunland
There are several birds and beasts who involve themselves in the wars for Middle Earth, including the Ravens of the Lonely Mountain, who have long been friends to the dwarves who dwell there. The ravens help to pass messages across the battlefield for Thorin and his company during the Battle of the Five Armies.
In opposition, the Crebain of Dunland are devious, crafty crows who have sided with Saruman due to an old allegiance with the wild-men of the Southlands. They act as spies who report on the comings and goings of the fellowship as they journey towards Mordor to try to destroy Sauron’s ring of power.
Ents vs. Huorns
Ents are well known for their involvement in the defeat of Isengard, when they helped to take down the white wizard Saruman after he made the mistake of chopping down their trees. These shepherds and herders of the forest are well known for being slow and gentle giants, who never do anything hasty.
On the other hand, their counterparts the Huorns are cruel and deadly creatures. They appear out of the forest in the blink of an eye and take great pleasure in trampling their victims to death.
Eagles vs. Fell Beasts
Many think that Fell Beasts are giant eagles who have been infected by Sauron’s greed and poison so badly that they lost all of their feathers. In fact, they are an entirely separate species. Nonetheless, they can be considered the giant eagles' evil opposites, because they are a perfect match in size and strength.
These creatures have wings more likened to bats, and sharp teeth rather than beaks. They often come head to head with the giant eagles as the birds try to protect the peoples of the world from meeting the horrible fate of being picked off one by one from above.
Noble Steeds vs. Wargs
Horses play an incredibly important part in both The Hobbit and the Lord of the Rings. They are the bravest companions in every battle, and they save the heroes of the story on countless occasions. They are friends to the elves, and treasured by the people of Rohan who ride across the lands on their backs.
On the other hand, there are the wargs, who serve the same purpose for the orcs. These wolf-like creatures are often depicted as snarling and rabid, and have none of the gentle beauty and grace of the horses, but help their masters cross vast distances quickly.
Elves vs. Orcs
Orcs are believed to be elves who were corrupted by Morgoth long ago, back when Middle Earth was still young. Morgoth created all sorts of evil beings, and orcs are probably the vilest and most disastrous because they spread and kill wherever they go. They are greedy and selfish and absolutely brutal, which is the complete opposite of the elves they are believed to originate from.
Elves are the oldest beings in the world, the very souls whom Middle Earth was created for. The orcs, by contrast, have been an enemy and a pestilence to them ever since the first one was corrupted.
Dwarves vs. Goblins
Dwarves are no walk in the park; in fact, they are often stubborn, grumpy, and unnecessarily proud. However, despite their flaws, most of them are extremely loyal, brave warriors with good hearts. There’s not a lot that dwarves wouldn’t do to protect their loved ones, and their deep mines under the ground are home to some of the most exquisite and beautiful works of creation known in history.
In a far cry from this, their evil counterparts the goblins, who also like to dig deep tunnels below the earth, are power-hungry and gluttonous. They too, covet gold and great wealth, but are willing to go to far more nefarious and detestable lengths to get it, as is seen in Peter Jackson’s movie adaptation of The Hobbit.
Pure Maiar vs. Tainted Maiar
The Maiar are some of the earliest beings ever created, and also some of the most powerful. Each of the maiar has certain abilities and magic in order to help them achieve their mission of protecting the peoples of the world.
The maiar who stay true to their mission and try to shape and guide the narrative positively are the good characters like Gandalf and Radagast and Shadowfax. On the other hand, their evil counterparts are those who put their own selfish gain above their intended purpose, and chose dark magic and dominion over light, like Saruman and Sauron.
Men vs. Wraiths
As the War of the Ring comes to pass at the end of the Third Age, the entire fate of Middle Earth rests in the hands of men. There are many incredibly brave, loyal, and true characters in this race, including Aragorn, Eowyn, and Eomer, who help the heroes to victory.
But there is also a lot of fear within the world of men who are easily corrupted. This is shown by the Ring-wraiths, the nine servants of Sauron. They were once great kings, but have now become nothing more than shadows of themselves as they gave in to temptation and power-lust.
Hobbits vs. Gollum
Finally, the hobbits of the Shire, arguably the most peaceful beings in existence, want nothing more than a quiet and simple life. Yet, they are always thwarted by Gollum. He was once a Stoor himself, an ancestor to the hobbits, but he became twisted and poisoned by hundreds of years in the possession of the One Ring.
Gollum is the biggest obstacle in Frodo and Sam’s path as they try to venture to Mount Doom to throw the dark object in the fire. But as always, the heroes prevail in the end.