Durin’s Bane

When the Valar came against Morgoth at the end of the First Age, most of his servants were destroyed, but some few fled into the world and hid themselves in dark places. One such was a Balrog, quite possibly the last of its kind in Middle-earth, that escaped into the east from the ruin of Angband and buried itself in the roots of the Misty Mountains beneath Khazad-dûm.²

For more than five millennia, the Balrog 'slept' in its deep hiding place (perhaps it was using this time to grow in power, or rebuild its physical form). It remained undisturbed as the Second Age passed, and long into the Third. At last, the mithril-miners of King Durin VI stumbled upon it and it awoke from its long sleep.³ Durin was slain by the creature and his son Náin I became King.

It seems that, under Náin, the Dwarves attempted to make a stand against the Balrog, but it was a power too great for them to control. For a year, they attempted to hold their mansions against it, but at last Náin and many of his subjects were slain, and the survivors fled from their ancient halls. At this time too, many of the Silvan Elves of Lórien left their land and escaped into the south.

For some five hundred years, Moria (as Khazad-dûm became known) was deserted but for the Balrog. In around the year III 2480, though, Sauron began to put his plans for war into effect, and as part of these, he sent Orcs and Trolls to infest the Misty Mountains and bar the passes from Eriador into Rhovanion. Some of these creatures came to Moria.

We are not told whether Sauron was aware of the Balrog's existence until then - certainly the exiled Dwarves had not recognised what kind of creature Durin's Bane was. It appears that the Balrog acknowledged Sauron's authority, if only because it allowed his creatures to remain in Moria. In addition, the messenger of Sauron who came to Dáin II Ironfoot offered to return Moria to the Dwarves, strongly suggesting that the Balrog was under Sauron's power.

Despite an ill-fated attempt to recolonise Moria by Balin in III 2989, Durin's Bane remained a dark and brooding menace in the ancient kingdom of the Dwarves, whose nature was hidden to the outside world.

In January III 3019, the Company of the Ring travelled through Moria on the Quest of Mount Doom. In Gandalf, the Balrog finally encountered a being of the same order and power as itself. As the two Maiar faced each other on the Bridge of Khazad-dûm, Gandalf broke the Bridge and the Balrog fell into the depths, but Gandalf too was drawn into the abyss.

Both survived the fall, and Gandalf pursued the Balrog for eight days through the deepest caverns beneath Moria. At last they came to the Endless Stair, and climbed the steps that led to the peak of Zirakzigil. There Durin's Bane fought its last battle - for two days and nights, the Balrog battled with Gandalf, but at last it was cast from the peak, and broke the mountain-side as it plunged to its doom.