It was a great shadow, in the middle of which was a dark form, of man-shape maybe, yet greater; and a power and terror seemed to be in it and to go before it.
It came to the edge of the fire and the light faded as if a cloud had bent over it. Then with a rush it leaped across the fissure. The flames roared up to greet it, and wreathed about it; and a black smoke swirled swirled in the air. Its streaming name kindled, and blazed behind it. In its right hand was a blade like a stabbing tongue of fire; in its left it held a whip of many thongs.
“Ai! Ai!’ Wailed Legolas. ‘A Balrog! A Balrog is come!’ Fili stared with wide eyes. ‘Durin’s bane!’ He cried, and letting his axe fall he covered his face. ‘A Balrog,’ muttered Gandalf. ‘Now I understand.’ He faltered and leaned heavily on his staff. ‘What an evil fortune! And I am already weary.’
The dark figure streaming with fire races towards them. The orcs yelled and poured over the stone gangways. Then Boromir raised his horn and blew. Loud the challenge rang and bellowed, like the shout of many throats under the cavernous roof. For a moment the orcs quailed and the fiery shadow halted. Then the echoes died as suddenly as a flame blown out by a dark wind, and the enemy advanced again.
‘Over the bridge!’ Cried Gandalf, recalling his strength. ‘Fly! This is a for beyond any of you. I must hold the narrow way. Fly!’ Aragorn and Boromir did not need the command, but still held their ground, side by side, behind Gandalf at the far end of the bridge. The others halted just within the doorway at the hall’s end, and turned, unable to leave their leader to face the enemy alone.
The Balrog reached the bridge. Gandalf stood in the middle of the span, leaning on the staff in his left hand, but in his other hand Glamdring gleamed, cold and white. His enemy halted again, facing him, and the shadow about it reached out like two vast wings. It raised the whip, and the thongs whined and cracked. Fire came from its nostrils. But Gandalf stood firm.
‘You cannot pass,’ He said. The orcs stood still and a dead silence fell. ‘I am a servant of the secret fire, weilder of the flame of Anor. You cannot pass. The dark fire will not avail you, flame of Udûn. Go back to the shadow! You cannot pass.’
The Balrog made no answer. The fire in it seemed to die, but the darkness grew, it stepped forward slowly on to the bridge, and suddenly it drew itself up to a great height, and it’s wings were spread from wall to wall; but still Gandalf could be seen, glimmering in the gloom; he seemed small, and altogether alone: grey and bent, like a wizened tree before the onset of a storm.
‘You cannot pass!’ He said. With a bound the Balrog leaped full upon the bridge. It’s whip whirled and hissed.
‘ He cannot stand alone!’ Cried Aragorn suddenly and ran back along the bridge. ‘Elindil!’ He shouted. ‘I am with you, Gandalf!’ ‘Gondor!’ Cried Boromir and leaped after him.
At that moment Gandalf lifted his staff, and crying aloud he smite the bridge before him. The staff broke asunder and fell from his hand. A blinding sheet of white flame sprang up. The bridge cracked. Right at the Balrog’s feet it broke, and the stone upon which it stood crashed into the gulf, while the rest remained, poised, quivering like a tongue of rock thrust out into emptiness.
With a terrible cry the Balrog fell forward, and its shadow plunged down and vanished. But even as it fell it swung its whip and the thongs lashed and curled about the wizard’s knee, dragging him to the brink he staggered and fell, grasped vainly at the stone, and slid into the abyss. ‘fly, you fools!’ He cried, and was gone.