The rising heat left no doubt, the Balrog was stirring.

Sylas and Gandalf exchanged grim looks; they both knew how dreadful such a foe was. Neither wished to squander strength battling mere Orcs, only to be left powerless when the true terror appeared.

"Don't waste yourselves here!" Gandalf called, his voice carrying over the clash of steel. "Through Durin's Bridge! To the First Hall! Quickly!"

He turned to the dwarves, staff raised like a beacon. "These Orcs are not acting alone. There is an older and far greater evil behind them, driving them forward. That shadow is coming for us!"

Balin did not hesitate. "Forward, sons of Durin!" he cried, rallying his warriors. The dwarves surged ahead, forming a shielded wedge to break eastward. Sylas and Gandalf stayed at the rear, holding the line against the howling pursuers.

They moved swiftly, yet the heat grew worse with every step. The air shimmered like midsummer, and sweat poured beneath the dwarves' heavy armor. Each breath was a struggle, as though the mountain itself were burning from within.

And still the Orcs pressed them, shrieking with fanatic zeal.

At last, the fellowship burst into the shadowed expanse of Durin's Bridge. The span stretched fifty feet across a black abyss, narrow as a cart's axle, with no guardrails to keep one from plunging into the endless dark. Long ago it had been built as the last defense of Khazad-dûm, no army could cross it except in single file. Yet the masons who crafted it had never dreamt the enemy would come not from the east or west, but from the firelit gulf below.

Already the stone beneath their boots was scorching hot. Gandalf stepped forward, peering into the abyss, and his eyes caught the glimmer of flame far below. His face hardened. "Quickly, across the bridge!"

But a thousand dwarves could not cross such a perilous span in moments. The bridge was too narrow. Sylas raised his wand:

"Engorgeo Pontem!"

With a resonant hum, the stone groaned and widened, expanding into a broad causeway, wide enough for a dozen dwarves abreast. The company gasped in wonder, then poured across in a rush, boots clanging as they fled to the far side.

Only Gandalf and Sylas lingered, standing guard. The abyss roared with fire, and the air grew blistering hot. The flames below licked higher, as if the mountain's heart itself were rising to consume them.

Sylas reached into his satchel and pulled free two small crystal phials. "Here," he said, pressing one into Gandalf's hand. "A fireproof draught, I brewed it myself. Even dragonflame cannot burn through it for a short while. Drink quickly!"

Gandalf uncorked the potion without question.

The potion worked swiftly.

Sylas drank it down in one draught, shivering as a chill swept through his body like a rushing tide. The unbearable heat of the stone bridge seemed to vanish in an instant, leaving him clear-headed and steady.

There was no more time to prepare. The last dwarf had scarcely set foot on the bridge's far side when the abyss below erupted. From the chasm surged a colossal shape wreathed in flame, Durin's Bane, the Balrog of Moria. Its fiery whip cracked against the air as it lunged upward to strike.

Sylas raised his staff and conjured a vast shield of shimmering force. The dome spread wide, enveloping him, Gandalf, and the dwarves clustered behind. The fiery lash struck the barrier with a thunderous crack, sending ripples of light across its surface, but the shield held.

Gandalf's eyes blazed. "Do not falter! Run to the East Gate!" he commanded. Balin needed no urging; he gathered his warriors and pressed them forward, their boots thundering as they raced away.

Now only Gandalf and Sylas stood upon the bridge, barring the path. The Balrog's whip recoiled like a serpent, then it drew forth a blade of living fire. The sword blazed with orange light, its heat so fierce that nearby Orcs were incinerated to ash where they stood. Yet the survivors did not retreat. Instead, they fell to their knees in fear and devotion, their eyes gleaming with worship.

But Gandalf and Sylas remained unmoved. Thanks to the fireproof draught, the burning air licked at their robes without harm. They stood ready, grim and defiant.

The Balrog's form was now revealed in full: a towering giant of flame and shadow, horned like a bull, eyes burning with malice. Dark wings of smoke stretched behind it, and its mane of fire streamed like molten iron. It strode forward like a furnace given life, each step melting the stones beneath its feet.

With a roar, it raised its blazing sword and brought it down upon them. The strike shattered Sylas's shield in an explosion of sparks.

"Lend me your blade!" Gandalf cried.

Sylas flung him the sword. Gandalf seized it, lifting it high. His voice rang out, resounding through the abyss:

"I am a servant of the Secret Fire, wielder of the flame of Anor! The dark fire will not avail you, flame of Udûn!"

The blade in his hand ignited with white brilliance, brighter than the stars. He swung it to meet the Balrog's sword, and when the weapons clashed, a shockwave tore through the bridge. Both Gandalf and the Balrog staggered back from the force.

Sylas raised his staff. From its tip burst a jet of emerald light, the Killing Curse, Avada Kedavra. It flashed across the air like a bolt of green lightning. The Balrog snarled and cleaved down with its fire-sword, the two powers colliding in a thunderous explosion. The shock shattered the Balrog's sword into fragments, and the blast flung the creature backward in fury.

Gandalf steadied himself on his staff, his breath ragged. Sylas's face was grim. His deadliest curse, which had felled countless foes, had not slain the demon, it had only shattered its blade. The Balrog was wounded, yes, but still strong.

From across the ruined span, the Balrog let out a roar that shook the mountain. Flames and shadow billowed upward like a storm. It swept its whip again, sending a flood of fire surging toward them like a crashing sea.

Sylas thrust his staff to the ground. "Aqua Muro!" he cried. From the earth burst a wall of surging water, a gleaming shield of waves to meet the inferno. The flames struck, boiling and steaming, devouring the wall as fast as he could conjure more.

At his side, Gandalf lifted his blazing white sword high, summoning a dome of radiant light. "Back to the shadows, servant of Morgoth!"

The Balrog's whip lashed the shield again and again. Each strike dimmed it, shrinking the circle of light. Gandalf gritted his teeth, pouring his strength into the spell, but in the end the radiance shattered with a final crack.

He staggered, leaning heavily on his staff, his chest heaving.

Sylas saw the Balrog raise its flaming whip again and quickly hurled a small leather case into the air. It burst open mid-flight, shattering under the force of the demon's strike.

What followed was chaos. The magic of the Traceless Extension Charm broke, and in an instant, everything stored inside was released. A torrent of water, enough to flood a football field, came roaring out, crashing against the Balrog in a hissing wave. Steam exploded upward, the sound like a thousand serpents shrieking in fury.

The water could not quench the demon's fire, but it unsettled the beast, its flames crackling and dimming under the sudden deluge. Yet among the flood came something far more dangerous: the petrified Watcher in the Water, now restored to motion by Sylas's spell.

The Balrog froze for a moment, its fiery eyes narrowing in disbelief. The Water-Watcher, its ancient neighbor and sometime ally, should have remained confined to the lake outside Moria. Yet here it loomed, its tentacles writhing once more. The Balrog showed no hesitation, lashing out with its whip to tear the creature apart.

But before it could strike, the Watcher's jaws opened, and from its maw rose another head, serpentine, crowned with venomous fangs, eyes burning yellow.

Herpo the Basilisk had hidden within the Watcher's body like a parasite waiting to strike. Now its terrible gaze snapped forward, locking on the Balrog.

The demon staggered. Its spirit shuddered as though pierced by an unseen blade. The basilisk's eyes could not kill such a fallen Maia, yet even a Balrog could be shaken, its mind momentarily clouded by the weight of that deathly stare.

That heartbeat of weakness was all Sylas needed. Gripping his staff with both hands, he poured his magic into it, every fiber of his being focused. The gem at its tip blazed.

"Avada Kedavra!"

From the staff burst a beam of emerald light, thundered through the air, tearing the shadows as it hurled straight toward Durin's Bane.