The Balrogs were the most terrifying of the evil creatures which inhabited J.R.R. Tolkien’s Middle-earth. In their beginning they were Ainur ("Holy Ones"), creatures who were the offspring of the thought of Ilúvatar, the All-father, creator of the universe. The Ainur dwelt with Ilúvatar in the Timeless Halls and they sang for him, gradually uniting their voices into a great Music, the Ainulindalë.

The Music preceded a great Vision made by Ilúvatar which revealed to the Ainur the essence of the themes they had sung for him. Melkor, greatest of the Ainur in strength and majesty, had strewn discord among the Ainur as they sang. And seeing the Vision he desired it as much as any of his brethren. When Ilúvatar created Eä ("It is!"), the universe, to satisfy the desire of the Ainur for the Vision and the companionship of the Children (Elves and Men) he had shown them, Melkor and many other Ainur entered into Eä, bound to its confines from the Beginning of Time until its End.

Melkor and the chief Ainur labored through uncounted ages to create the stars and shape the far regions of Eä. But they came at last to give shape to Arda, the Kingdom wherein the Children would dwell. And Melkor seeing its beauty and the immeasurable flame of its youth, which he himself had brought forth, claimed Arda for his own. The other Valar opposed him and Melkor went away for a while. But when he returned he sought to take Arda by storm, and many lesser Ainur joined the Valar in repulsing him.

Again Melkor withdrew from Arda, but when the Valar rested from their labors and their vigilance relaxed Melkor descended upon Arda with a great host of Ainur, corrupt spirits who had elected to serve him. He drove the Valar from the heart of Arda and established a great refuge in the northern regions called Utumno. There the corrupted Ainur took shape in forms of horror such as pleased their master and expressed their own wills.

The Balrogs were "those spirits who first adhered to [Melkor] in the days of his splendour, and became most like him in his corruption their hearts were of fire, but they were cloaked in darkness, and terror went before them". The Balrogs’ weapons of choice were many-thonged whips of flame, but they could wield blazing swords in close quarters, and possessed great strength. Gothmog their Captain wielded a great black axe.

Through the following ages the Balrogs served Melkor in his many wars. They were defeated and dispersed by the Valar in the War of the Powers, and Melkor was taken captive. But the Balrogs escaped and waited for his return to Middle-earth, and in time he came. Melkor quarreled with his companion and ally, Ungoliant, a creature of great and terrible power. But when he cried out in pain and anguish during their struggle the Balrogs heard him, and rising from beneath the ruins of his fortress Angband they passed over the world and came to his aid "like a tempest of fire".

Afterward when the Noldorin Elves followed Melkor back to Middle-earth to retrieve the Silmarils, three jewels of superb and holy beauty and light, the Balrogs proved to be the deadliest of foes for the mighty lords and princes of the Elves. They mortally wounded Fëanor, first King of the Noldor to set foot in Middle-earth, and they captured his eldest son Maedhros.

Through the centuries the Balrogs stood guard around Melkor’s throne, or led his armies into battle. Only once were they defeated by an Elf. Lúthien, princess of Doriath, followed her lover Beren of the Edain (Men who had allied themselves with the Elves against Melkor) on his quest for a Silmaril from the crown of Melkor. Together they stole into Angband, Melkor’s fortress, and there she danced and sang for the Dark Lord and all his servants, enchanting them into a deep sleep.

Years after Beren and Lúthien escaped with a Silmaril, the Balrogs redeemed themselves. The Noldor and their allies assembled vast armies with which to assail Angband and take it once and for all. Melkor unleashed his hordes and creatures, and the Balrogs under Gothmog fought their way toward the banner of Fingon, High King of the Noldor. Gothmog fought with Fingon alone until another Balrog struck the Elven king from behind, and then Gothmog dealt him a fatal blow, cleaving the Elf’s head through his shining helmet with one stroke of the Balrog’s great black axe.

Melkor unleashed the Balrogs again when he sent his armies against the hidden Elf city of Gondolin. Nestled in deep mountains and protected by the Eagles of Manwë, Lord of the Valar, Gondolin was the last of the great Elven realms to fall before Melkor’s armies. The Balrogs led dragons and orcs and other dread creatures in attacking the city. They drove in on the Elves and slaughtered them mercilessly.

But the Elves of Gondolin were the most valiant of all their race, and there in the fountain of King Turgon Gothmog met his end, mortally wounded by the Elven lord Ecthelion, who in turn was slain by his foe. And when the city was lost and Elves fled in all directions, one great band led by Tuor of the Edain and his wife Idril, daughter of the king, was ambushed by Orcs and another Balrog. There the Elven lord Glorfindel leaped in front of the great creature and fought it to the death. In the end, mortally wounded, the Balrog tumbled to its death over a great cliff, but it took hold of Glorfindel as he drove it into the chasm and dragged him down with it.

One last great battle awaited the Balrogs. Hearing the prayers of Elves and Men, the Valar were at last moved to send aid against Melkor. They assembled a vast army and sailed to Middle-earth where they fought a long and deadly war. The Balrogs stood until the last against the Host of the West, but in the end were killed or fled away, deserting their lord at the very last. Only one was known to have survived the War of Wrath, and it took refuge deep under mountains far from the cold and bitter north.

There for thousands of years the last Balrog rested, sleeping or biding its time. When the Third Age of the Sun was nearly two thousand years old the Dwarves of Khazad-dum delved too deep in following a vein of precious mithril toward its source. They awoke or freed the Balrog, which set upon them with a fury the world had not seen since the War of Wrath. It slew two Dwarven kings and slaughtered a great many of their folk, until at last the Dwarves fled their ancient mansions into a long and wearying exile.

There in Khazad-dum, called Moria ("Black Pit") by the Elves, the Balrog waited more than a thousand years. Tolkien does not say why it chose not to emerge and trouble the wide world. Perhaps the terror of the Valar in their righteous fury still ruled its heart. Perhaps it was merely cunning and biding its time until a change of days and fortunes came.

When the Third Age came to an end the One Ring of Sauron was found and taken up by Frodo Baggins, a hobbit. On the advice of the wizard Gandalf the Grey Frodo agreed to carry the Ring to the one place where it might be destroyed, and so an end brought to Sauron’s evil forever. But the path led through Moria, and the Balrog now strengthened by hordes of Orcs and Trolls discovered the Company of the Ring before Gandalf, Frodo, and their companions could escape.

This Balrog was cunning, testing its prey first by sending Orcs and Trolls against them. When it chose to intervene it discovered Gandalf laying a spell on a door. The spell would have confounded a lesser creature, but Gandalf sensed the great power of his foe and he used a Word of Command to seal the door permanently. The resulting collapse of that part of the subterranean city only delayed the Balrog for an hour. It freed itself and followed the Company by an alternate route.

In the final confrontation the Balrog revealed itself openly, and Gandalf chose to face it alone. He stopped its advance on a narrow ancient bridge, and sent the Balrog tumbling into the chasm which the bridge spanned. But the Balrog caught Gandalf with its whip, and drawing him down with it initiated an 11-day battle that ranged through deep-buried chambers up through long-forgotten roads of Moria to the high peak of the mountain under which the city was buried.

Fire, darkness, terror, whip, sword -- all the Balrog’s weapons and great strength failed it in the end. Gandalf prevailed at last and cast down his foe. Even in death its impact ruined the mountain side, and so grievous were the wounds it had inflicted on Gandalf that he, too, perished.

So great were the terror and power of the Balrog of Moria that many believe if it had captured Frodo and the One Ring it would have become an even greater menace than Sauron himself. The One Ring contained the bulk of Sauron’s power, and combining that with its own the Balrog could have launched a new age of evil unlike any since Melkor himself had ruled the world from Utumno and Angband.