The rising heat could only mean one thing: the Balrog was coming.

Kael and Gandalf knew the terror of such a foe. They refused to waste strength on orcs and risk being drained before the true fight.

"Don't get bogged down with the orcs. Cross Durin's Bridge to the First Hall!" Gandalf shouted to the dwarves. "These orcs are being driven by an older, greater evil. It's coming out!"

Balin didn't hesitate. He ordered the dwarven warriors to push east with everything they had. The dwarves broke through at the front while Kael and Gandalf covered the rear.

They hurried on without a pause. The air heated like sudden midsummer, and armor began to steam on dwarven shoulders. The Balrog was close.

The orcs never stopped pursuing. Feeling the change, they grew frenzied, terrified, and ecstatic in equal measure. Moria's orcs worshiped the Balrog as a god, served its will, gathered its intelligence, and guarded its domain. Azog, whom Kael had slain, had been their leader and the Balrog's servant. The hatred had a history.

They repelled the press of orcs and ran hard for Durin's Bridge.

They reached it at last, a narrow, rail-less span about 50 feet long, arching over a black chasm between the First and Second Halls. Built as a final defense, only one file could cross at a time. The old dwarven craftsmen had never imagined the enemy would come not from east or west, but from below.

Now the heat was almost unbearable. Gandalf stepped to the edge and peered downward. Fire flickered far below. He tensed as if staring into doom.

"Across the bridge, quickly!"

Getting over a thousand across a one-file bridge was impossible in time.

Kael lifted his staff and cast on the stone, "Engorgio!"

The span widened at once until over a dozen could run side by side.

"Go!" he called.

The dwarves surged across, sprinting for the far side. Kael and Gandalf held the rear. As the last dwarves cleared, a roar of flame surged up from the chasm and licked at the bridgehead.

A long whip of fire lashed out of the depths straight for them.

"Protego Maxima!" Kael raised his staff and poured magic into a dome that sealed him, Gandalf, and the dwarves behind them. The whip struck, and ripples shimmered across the barrier.

"Don't stop. On to the First Hall, the east gate!" Gandalf bellowed. Balin took one look at the lashing fire and led the dwarves deeper, knowing they could not help by staying.

With their backs clear, Gandalf joined Kael to face the ancient terror.

The fiery whip snapped back into the pit.

Then a mass of searing orange fire surged up and landed on the far side of the bridge. Orcs too slow to flee turned to ash in an instant. The rest kept their distance, eyes wide with fear and worship.

Kael and Gandalf stood closest. The fire-protection draught kept the heat from biting, but both were grim and ready.

Within the blaze stood a giant silhouette, a core of blazing fire wreathed in writhing shadow. Its eyes burned yellow. A mane of flame and steam haloed its bull-like head beneath two great horns. Wings of shadow trailed behind; a long tail of fire thrashed. The very air wavered around it, and stone began to sag and glow at its feet.

A Balrog. A fallen Maia. Alone, it had shattered Khazad-dûm and held it for millennia.

Perhaps seeing them unharmed by its heat enraged it. Flame surged higher as it drew a great sword of burning fire and black smoke and hewed at them. The fiery blade shattered Kael's barrier in one stroke.

"Kael, lend me your Flammifer!" Gandalf called.

Kael tossed it. Gandalf caught the sword, set his staff, and faced the fire.

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

His voice rang over the abyss, equal parts declaration and spell. The Flammifer flared with white-hot, holy brilliance. He met the Balrog's blade. The clash boomed like thunder and drove both back several steps.

"Avada Kedavra!"

Kael lifted his staff and sent a lance of blazing green death across the span. The killing aura was heavier and denser than he'd ever conjured.

Sensing mortal peril, the Balrog reacted instantly and cleaved the curse with its blade. Curse and sword met and detonated in a flood of green light that erased the air between them. The Balrog staggered; its fire-sword fractured into shards.

The blast shoved Kael and Gandalf back on their heels. They steadied and watched it across the broken span.

Kael's stomach sank. A fully charged Killing Curse, and only the sword was gone. That was not the crippling blow he had hoped for.

No time to dwell. He focused and readied again.

The Balrog roared. A tidal wave of fire surged toward them.

"Aguamenti Maxima!"

Kael drove his staff. A wall of water surged up and met the inferno. It hissed and flashed to steam, the wall boiling away faster than he could replenish it. He forced more water through, a continuous torrent barely holding the blaze.

Gandalf raised staff and sword, crossing them overhead to cast a swelling shield of light. "Back to the shadow, servant of Morgoth!"

The light drove the demon-fire back. The Balrog's whip cracked and struck the shield again and again, shrinking it ring by ring. Gandalf gritted his teeth and widened it, but even as a fellow Maiar, his power was veiled while the Balrog's burned unfettered. The shield collapsed in a shower of radiance. He stumbled, bracing on his staff, breath coming hard.

"Balrog, try this!"

Kael hurled a leather case from his space bag. The flaming whip snapped and smashed it midair. The case burst; the pocket space collapsed, vomiting its contents. A mass of water the size of a field crashed down on the Balrog, hissing like iron plunged in a quench. It did not extinguish that imperishable blaze, but it made the demon falter.

Along with the flood came a colossal stone form, the petrified Watcher in the Water.

The Balrog knew the shape. Its ancient neighbor. One lorded over Moria; the other claimed the lake. Puzzlement flickered in the fire of its eyes. Why was it stone?

It did not matter. It raised the whip to smash the obstacle aside.

A serpent's head lunged from the Watcher's half-open maw. A pair of yellow eyes met the Balrog's gaze for a heartbeat.

Basilisk Herpo had hidden in the statue and struck by surprise.

That gaze hit like a hammer on the soul. A fallen Maia could not be killed by it, but even a heartbeat of blankness was enough.

Kael seized the opening.

He planted his feet, gripped the staff with both hands, poured everything into it, and spoke with a voice like a verdict.

"Avada Kedavra!"

Emerald lightning, pillar-thick, tore across the broken span toward the Balrog.