Today's Date in the Shire
The Fellowship of the Ring remains in Lothlorien.
Fun and Games
Walk to Rivendell
Malbeth the Seer
The lieutenants of Morgoth; Demons of fire; Dúrin's Bane.
Balrogs (Quenya Valaraukar, both meaning 'Demons of Might') were Maiar corrupted to the service of Melkor at the beginning of time. They appeared as large shadowy figures, from whom fires spread as manes and thongs; they were armed with black weapons and always with fiery whips. In the First Age, Balrogs served as commanders and sometimes in packs as elite shock troops in Morgoth's armies.
During the captivity of their master in Valinor, they gathered and hid in the northern fortress of Angband. When Morgoth spead eastwards after the rape of the Silmarils and was assaulted by Ungoliant at Lammoth, the Balrogs issued forth from their hideout and came to rescue Morgoth from her entangling webs.
After Morgoth had organized his lair and his troops, armies led by Balrogs soon spread terror over Middle-Earth. The Noldor who had just landed at the shores of Middle-Earth were attacked by an army of orcs, who were led by Gothmog, the Lord of the Balrogs. Feanor crashed into Gothmog and his bodyguard when he pursued into the enemy's army, and was overwhelmed by them.
In the Nirnaeth Arnoediad, Gothmog and his troll-guard also defeated Fingon, High King of the Noldor, and overwhelmed Húrin Thalion, whom they took captive with their lashes and thongs of fire, and dragged to Angband.
With the War of Wrath and the Host of the Valar came the doom of the Balrogs. With uttermost valour, the elven lord Glorfindel slew a Balrog in single combat; and, in front of the court of Gondolin, Gothmog was defeated by Ecthelion. The majority of the Balrogs fell in the breaking of the Thangorodrim and the collapse of their fortress Angband. Some, however, were able to flee in time and from then on hid in the deepest pits underneath the mountains.
Such was the Balrog whom the dwarves under Dúrin VI excavated in Khazad-Dûm in the Third Age. Driven by their greed for mithril, they delved ever deeper and roused this demon in one of the deep caverns under the Misty Mountains. Dúrin VI was slain by the Balrog, and only one year later, his son, Náin I, fell under Dúrin's Bane - as the Balrog was soon called -, too. Dáin Ironfoot and the other dwarves abandoned Khazad-Dûm, and the terror in the eyes of these witnesses made Thráin drop his plan of reconquering the mines.
When the company of the Ring-bearer, led by Gandalf, was about to cross the Bridge of Khazad-Dûm in their underground journey through Moria, they had to recognize, to their terror, what the orcs they had met before meant with their cries of 'fire': the Balrog, Dúrin's Bane, had again risen. It stood in the middle of the bridge, as a giant creature of fire and shadow, with a mane of flames, a many-thonged whip, and a vast shadow about it, like its wings 'spread from wall to wall'.
Gandalf challenged the demon, and commanded the company to run for their lives. The wizard hew the bridge under him asunder with a thrust of his staff, warded off the blows of the Balrog's blade of leaping fire and fell to the deepest ground at the very bones of the earth, all the while clutching with the Balrog. From there their fight continued to the top of the Celebdil, from where the Balrog crashed to his doom onto the mountainside.
All the literary and mythological importance of the Balrogs, however, cannot be compared with the debates they created among Tolkien's readers. This is because the descriptions on Balrogs are never so clear or consistent as to clearly convey whether they had wings or not. The description of the Moria-Balrog as well leads to this impression as it might provide arguments against Balrogs having wings.
One thing is for sure: Middle-Earth would have created a good deal less of literary discussion without Balrogs and the mystery of their wings.