In LOTR with Harry Potter system

After quietly slipping out of the hidden chamber, Bilbo crept toward the treasury.

The grand hall that lay beyond was vast, truly vast, its walls lost behind glittering towers of gold, silver, and jewels. The treasure shimmered in the dim glow that filtered in from high windows and cracks in the stone, casting a warm light across the room.

Bilbo stood at the threshold, utterly awestruck. Never in his life had he seen such wealth. It was beautiful. Terrifyingly beautiful.

But that awe was quickly replaced with dread.

How in the world was he supposed to find a single gem, an Arkenstone the size of a clenched fist, amidst all this?

The treasure stretched endlessly before him like a golden ocean. Even with luck on his side, it was like trying to find a needle in a mountain-sized haystack.

And then there was the other problem.

The Dragon.

Bilbo instinctively glanced around, scanning the shadows. He saw no sign of Smaug. 

Where had the creature gone?

The silence was unnerving. Was the Dragon hiding? Sleeping?

The thought sent a chill through him.

But when Bilbo glanced down at himself, his limbs faintly outlined by the shimmer of Sylas's Disillusionment Charm, and remembered all the protective enchantments wrapped around him like invisible armor, he felt a little steadier.

He tiptoed forward, the gold coins shifting beneath his feet without a sound.

Hobbits, with their wide, soft soles, were naturally silent. And with Sylas's charms lightening his steps, Bilbo moved like a ghost, not disturbing a single coin enough to clink.

And so, he began to search.

Carefully. Slowly. Quietly.

It wasn't easy. His heart raced with every movement. The sea of treasure sparkled temptingly, but the Arkenstone was nowhere in sight.

He combed through heaps of necklaces and goblets, stumbled past crumbled helms and ancient blades. The deeper he went, the more hopeless it felt.

But then, luck, or perhaps fate, led him to the highest mound in the hall.

And there, perched at its peak, was a gem unlike any other.

It wasn't large, about the size of a Hobbit's fist, but the moment Bilbo laid eyes on it, he knew.

This was the Arkenstone.

Thorin hadn't described its shape or cut, only saying: "You'll know it when you see it." At the time, Bilbo had been skeptical.

But now, he understood.

The Arkenstone shone with a cold, white brilliance, flawless and smooth. Inside, it shimmered as though it held a fragment of the night sky, a swirl of starlight and depth like a galaxy trapped in crystal.

Forged by time and the hands of Dwarves deep within Erebor, it had once adorned the throne of the King Under the Mountain. Not just a gem, but a symbol of kingship of Durin's line and the might of the Dwarven people.

The moment Bilbo laid eyes on the Arkenstone, joy lit up his face. Without hesitation, he scrambled up the gleaming mound of gold, reaching eagerly for the shining gem perched at its peak.

But just as his fingers brushed the air above it;

The treasure shifted.

A deep rumble echoed beneath him, and before he could react, the entire golden mountain began to collapse in a clattering landslide. Coins and gems spilled like a river of fire, and the Arkenstone vanished within the cascade.

Bilbo didn't have time to mourn its loss.

From beneath the shifting treasure, a massive form began to rise.

His eyes widened in horror.

He had been standing atop the Dragon's head.

Smaug!

With a startled gasp, Bilbo leapt off the emerging beast, rolled down a cascade of rubies and crowns, and fled, his heart hammering in his chest.

Behind him, the Dragon's eyes snapped open. Twin vertical pupils, glowing like molten gold, narrowed in on the blur of Bilbo's Disillusioned form.

"A thief," Smaug hissed, his voice as smooth as molten metal, "but not Dwarf, nor Man. What are you?"

His long, sinuous tail lashed behind him, circling Bilbo's escape path like a fiery trap.

"What spell cloaks you, little whisper in the dark? I see no form… but I smell you. I hear you. I feel your breath trembling in the gold."

Bilbo froze.

There was no way out.

The Dragon's hulking body exuded heat like a forge, and the sheer weight of his presence seemed to press the very air down around them.

Swallowing hard, Bilbo tried to steady his voice.

"Ah...Smaug the Magnificent," he stammered, offering a hesitant bow. "I...I'm just a humble Hobbit. I wandered in quite by accident. Very sorry. I'll just… be going now."

Smaug's eyes narrowed, and a cruel smirk curled at the edge of his enormous mouth.

"'Accident,' he says. Hmph. Every thief spins a tale of innocence when caught."

His voice dropped, low and dangerous.

"I have seen many would-be burglars over the centuries. Each one cloaked in lies and sweetness. None of them left with their lives."

A red glow built in the Dragon's chest.

"Would you like to know what became of them?"

Bilbo took a step back. "W-what?"

"They were incinerated," Smaug growled. "Turned to ash in a breath of Dragon-fire."

As the heat intensified, fire crackling at the edges of the Dragon's maw, Bilbo knew he had no time to hesitate.

He reached into his pocket and slipped on the One Ring.

In an instant, the world shifted, his body disappeared, cast into the realm of shadows. The wraith-world swallowed him whole, rendering him invisible to mortal eyes.

Smaug snarled, confused, his flame sputtering as he turned his head left and right.

"Where are you, little worm?" he hissed. "Gone? Or merely hidden?"

His tail lashed again. "I feel you. Still here. Still near. You wear something... something ancient. Not of Dwarves. Not of Men."

He sniffed the air.

"Gold… yes, but not just gold. I smell old magic. A gift from an enemy long forgotten. A friend of the shadow, perhaps?"

His voice became smooth, almost seductive.

Bilbo, still cloaked in shadow, trembled. Smaug's voice pulled at something within him, something deeper than thought, whispering to his heart.

And before he could stop himself…

His hand moved.

He removed the Ring.

And reappeared, blinking, directly in Smaug's line of sight.

"Aha! So you're here!" Smaug's eyes flared like twin furnaces, gleaming with savage glee.

Bilbo's breath caught. Panic surged through him. With trembling fingers, he reached into the enchanted pouch Sylas had given him and yanked out the Mandrake.

With all his strength, he hurled it at the Dragon.

The pot shattered against the golden floor, and in the next instant—

A scream erupted.

The Mandrake's enchanted shriek tore through the air, bouncing off gilded walls and echoing like a banshee's curse.

Smaug reared back, bellowing in pain. His massive head swung violently as though trying to shake the sound from his skull. His claws scraped across the gold, creating sparks, while his wings beat the air in a frenzy.

Though the cry couldn't kill a Dragon of his might, it drove deep needles of torment into his mind, deafening, disorienting, maddening.

The beast thrashed wildly, overturning entire mountains of gold. Crowns flew, scepters shattered, and ancient armors crumpled under his rage.

Finally, with a heaving roll, Smaug buried the Mandrake beneath tons of treasure, cutting off the sound.

Silence returned.

But the Dragon's pain turned swiftly to fury.

His head whipped back toward the Hobbit, eyes blazing with rage. His voice came like thunder cracking through stone.

"You little wretch! You will pay for this!"

Bilbo, already running toward the exit, froze as the roar reverberated behind him.

"I will scorch your kind from the earth!" Smaug bellowed. "I will raze your villages! Your kin will burn!"

Bilbo's heart sank.

"No!" he shouted over his shoulder, nearly stumbling on a pile of rubies. "They know nothing of this! The Shire has nothing to do with me!"

But the Dragon only laughed, a slow, cruel rumble of satisfaction.

"Oh, but they do now," he sneered. "They will all suffer for your theft. Their blood will be your burden!"

Bilbo's chest tightened with horror. Visions of the peaceful green hills of the Shire engulfed in Dragon-fire flashed before him.

He couldn't allow it.

He skidded to a halt, yanked the gold coin Sylas had given him from his pocket, and tapped it furiously. "Help me… please…"

The Dragon's shadow suddenly swept over him.

"Got you," Smaug hissed.

Bilbo looked up, and saw a gaping maw filled with fire.

But then;

"Avada Kedavra!"

A streak of emerald light cut through the air and struck the Dragon square in the chest.

It did nothing.

But it made Smaug falter for a fraction of a second.

"Sylas!" Bilbo cried, eyes lighting up with hope.

A streak of silver shot down from above, Sylas astride his broom, wand blazing with magic. With practiced speed, he dove toward Bilbo, scooped him up, and swung him onto the back of the broom.

Behind them, fire erupted where Bilbo had stood moments before.

Sylas flew low and fast, dodging golden columns and swirling clouds of ash.

He cast a glance back at the Dragon, unharmed.

Even the Killing Curse hadn't pierced the scales.

"A Wizard?"

His eyes narrowed, studying Sylas's features with wary curiosity.

"Who are you?" Smaug demanded. "And where do you come from?"