So this came from a request I got from someone on a while ago. Hope you guys enjoy!
The Secret of Erebor
Sometimes Fili got tired of his uncle's stubbornness. It was because of Thorin that they were in this mess. The whole of Middle Earth (or so it seemed) had turned up at Erebor's doorstep, wanting a share in Erebor's treasure. Either way, this problem could have been settled had Thorin given up some of his pride and relinquished some of the treasure to the Men of Dale and the Woodland Elves, but that wasn't like him.
Fili and Kili had to practically drag Thorin into council with Thranduil and Bard, and it took hours for Thorin to finally consent to fighting alongside the Elves against their common enemy, the goblins and the Wargs. It took relatively no time for Fili to convince Thorin to send a messenger Raven to Dain in the Iron Hills, pleading for aid in the battle. But even then, Thorin thundered out of the room, obviously angry at having to fight beside Thranduil. Fili did not see Thorin until right before they surfaced from Erebor for battle, as his uncle was in constant council with Gandalf and Dwalin and Dain (who had come as soon as he heard), planning battle strategies. Apparently, or so Fili had heard, Gandalf had sent word to the Lord of the Eagles and Beorn, asking for any assistance they could give against the two armies.
So while their uncle sat in a dark room, lit only by the roaring fire at its eastern end and a small candle on the table, Fili and Kili took to exploring the mountain, learning every secret it had to offer. They didn't know how long they would have within Erebor's halls, the battle looming right under their noses, and they wanted to appreciate the halls of their fathers before walking right to their doom. The outcome of the battle seemed already decided; the goblins and Wargs combined formed a legion far stronger than any of Thorin's company had expected, and it would take a miracle for them to win, much less come out of the battle alive.
Until one day, Kili found something. Something even Thorin might not have known about, something that could change the outcome of this war. Hidden deep within the mountain, in the farthest western point (and behind a secret door that Kili had only discovered because he'd tripped, fallen into the wall, and the door had opened) lay a golden bow. Obviously of Dwarven make, it fit within Kili's rough, calloused fingers perfectly. A quiver of arrows lay beside it, and the arrows appeared to be of pure flame, as if the flames from the forges had been sealed inside a small glass case. The feathers at the arrows ends seemed to move like a fire whipping in the wind, and were piping hot to the touch. To put it simply, it was beautiful.
After showing it to Fili and neither of them knowing what it was, they'd taken to Erebor's archives, searching through all the listings of every weapon ever made in the mountain. Nothing on the bow was to be found. Finally, Kili reached up for another book but two came out at him, one only about five pages long and obviously hundreds of years old. The bow was on the very first page.
Kili had hollered for his brother, whooping at shouting. The bow was the first and last of it's kind, and therefore the rarest weapon Erebor had to offer. It was made of a rare kind of gold, gold that was no longer produced in Erebor. There was no information on the arrows.
It was known as the Pheonix Valkyrie. And apparently, it was the only one of it's kind to have ever existed in the entire history of Middle Earth.
Fili and Kili had agreed not to show their uncle, worrying about his greed over the treasures of Erebor, and had instead taken it to Gandalf. Even the wizard, who had seen all of the ages of Middle Earth, was mystified by the bow. In placing his fingers on the arrows, a look of recognition crossed Gandalf's face.
"These are of phoenix blood. Pure flame, nonetheless. If fired, they burst into a phoenix-like shape, made entirely out of fire. This, if used properly, could change the outcome of the war. Keep it safe, Kili, and do not show Thorin. This bow belongs to you."
Kili had smiled and clutched his fingers tighter around his prize, his heart swelling. He, and he alone, would have a say in how the battle turned out. And he loved that kind of pressure.
Now, Kili and Fili stood on the front line, hoards of Elves, Dwarves, and Men behind them. Their Uncle stood next to them, pride commanding his every feature and making him appear as tall as the Elven king behind them. Goblins and Wargs snarled and hissed at them, almost making Kili's blood run cold. But he had his secret weapon, and he knew they would win.
Behind him, on the slopes of Erebor, the Pheonix Valkyrie lay perfectly hidden, out of sight for anyone that was over four and a half feet tall, and underneath a collection of stones and a magical cloak. Gandalf had aided in picking the spot and providing the cloak and Fili had watched them hide the bow, just so he could know where it was in case Kili couldn't get to it on time.
Kili was ready. He had his brother to his left, his uncle on his right, and his favorite sword within his clutches. Not only that, but he was dressed in Erebor's finest armor, light on his shoulders but tough and near impossible to pierce. Fili had adorned the same armor only a slightly darker shade of silver, and Thorin's was of pure gold. If they were going to die, then they'd die knowing where they came from and who they were.
Before Kili knew it, he was charging into the goblin ranks, slashing at anything and everything that got in his way. He felt Fili's presence beside him, and he moved so that he and his brother were back-to-back, slicing and hacking like a well-oiled machine. They were a force to be reckoned with, as was their uncle, whom they could see was cutting down everything that came into his path, working his way to Bolg.
Kili sliced off a particularly ornery goblin's head and laughed maniacally, enjoying the thrill of the battle around him. He let out cry after cry and grunt after grunt, using up most of the energy he had. He heard a loud roar to his left and the goblin in front of him started, giving Kili enough time to stab him through the heart and step out of the way before Beorn charged through the goblin ranks, his huge form cutting the goblins down like weeds.
But Kili wasn't paying attention. To his right, a goblin charged directly at him. It was only when the thing was right next to him did he move, avoiding getting his head chopped clean in two. But the goblin still found its mark.
The sword cut right into Kili's thigh, making him scream in agony. He collapsed to the ground, howling, blood seeping through his fingers.
Fili turned, shocked, before hacking away at the goblin that had hurt his baby brother, pure hatred masking his innocent features. He wrapped Kili's arm around his shoulders and retreated, Elves swarming around them and protecting them from further harm. Fili struggled with Kili up the hills at the mountains roots to where they had placed the arrow. The battle swarmed on below them as Fili let Kili gently down up against a boulder, giving him a moment's rest. Fili started to bind the wound, making Kili hiss with the pain.
"I'm sorry, brother," Fili sighed, "But now isn't the time. We need to find the bow and end this before it gets any worse."
Swallowing the tears that had begun to brim, Kili nodded and rose from where he sat, gasping when he couldn't put weight on his injured leg. Fili caught him before he could fall, and together they moved to where the bow was hidden. Kili leaned up against a large stone while Fili searched for the bow, and sighed with relief when he heard Fili's almost jubilant "A-ha!"
"Here," Fili said, handing Kili the bow and quiver. "Just stand here and fire. Remember what Gandalf said: the farther away we are, the better. Aim for Bolg, like killing a colony of ants. The goblins will be useless without a leader, and the Wargs will get caught up in the flame."
Kili nodded and placed the arrow on the bow's golden string. In one swift motion, he'd drawn the string back to his cheek, letting out a deep breath and closing his left eye.
But there was a problem. Thorin was still amongst the goblin ranks, still fighting with Bolg. And from the looks of it, their uncle wasn't anywhere close to winning.
"What are you doing?" Fili questioned, "We don't have time! Fire it!"
"I can't!" Kili moaned, "Thorin's in there!" Kili stared hard at Gandalf's back, pleading for the wizard to notice and move his uncle out of the way.
As if by magic, Gandalf turned and, seeing Kili paused with the bow in his hands, looked out at the battlefield. Upon witnessing Thorin still trapped in the goblin ranks, Gandalf strode forward. Thorin was knocked to the ground by a rough swing of Bolg's axe, and Gandalf was there, hauling Thorin by his hood.
Finally, Kili had the separation he needed.
The arrow let loose, as if on its own, and Kili gasped as it burst into the form of a large bird, as large as an eagle. Only this bird was entirely made out of flame.
The phoenix swept the goblin's side of the battlefield in one swift motion, encircling almost the entire legion in a twenty-foot wall of fire. Kili could see Thorin stumbling backwards in shock, and all the Elves, Dwarves, and Men retreated to Erebor while their enemy burned with the heat.
Almost out of relief, Kili fainted, and Fili had to lunge to catch him before he hit his head on the stone. It was over. The battle was won. But for Kili, the world turned black.
For nearly a week, Kili lay asleep. His wound had become infected, and he was in and out of fever. Gloin was attending to the youngster, but nothing was seeming to help. Fili never left his brother's side, clutching his brother's left hand in his own two hands, waiting for any sign that he might be awake. Gandalf had done all he could, and had left, needing to attend to the wounds of others. Thorin had visited multiple times, but had only stayed for short spells as he had diplomatic matters to attend to. Apparently, Thorin had agreed to relinquish some of the treasure to the Elves and Men for their aid, along with giving a larger portion to Dain for arriving so promptly. Thorin had also given his company their share, along with a shirt of Mithril rings to Bilbo. The hobbit had also visited Kili, providing some smelling salts from the Shire in the hopes that Kili might awaken.
On the fifth day at dawn, Kili's fever broke. Fili wiped away any drop of sweat that dared to swim down his brother's brow, and kept his baby brother as comfortable as he could. He told his brother everything that had happened, including the news of the Dwarves in the Blue Mountains leaving and coming to reclaim their homes in Erebor. Fili told Kili that they would be here in three weeks' time, provided no enemies got in their way, and he hoped that his brother would awaken by then.
On the sixth day when the sun was at it's peak, Kili squeezed at the fingers wrapping around his own and opened his eyes. Fili was immediately on top of his brother, his arm's wrapped around Kili in a tight embrace.
"I thought I'd lost you," Fili croaked, his voice cracking with tears.
Kili felt some of his own tears spring to his eyes, and he sighed into his big brother's shoulder. "I'm sorry, brother. I'm sorry I let the wound affect me that much."
"At least the goblin who did it is already dead," Fili joked, "now I don't have to get revenge."
Kili laughed heartily, and Fili smiled at the pure, bright noise, the warmth seeming to return to his heart.
Thorin came as soon as he heard and grasped at Kili, sighing with relief. "You had me worried, boy."
"Sorry, Uncle," Kili sighed.
Thorin sat at the foot of Kili's bed and stared at his nephew for a moment before asking, "So tell me…where exactly did you find the Phoenix Valkyrie?"
All was well. Fili and Kili's mother Dis had joined them from the Blue Mountains, completing their family. Erebor was close to full production again, and Kili and Fili went to Dale almost every day to aid in the city's reconstruction. Thorin was in his rightful place as King Under the Mountain, and Gandalf made sure he understood not to become too greedy.
They'd hidden the Pheonix Valkyrie in a place that only Kili, Fili, and Thorin knew about, and Thorin had made it perfectly clear that it was only to be used for the direst of emergencies, and was only to be used by Kili who had found it in the first place.
However, a moment of sadness came when the dwarves said goodbye to their beloved Burglar. Thorin had offered Bilbo a place amongst the Dwarves in Erebor, but Bilbo's heart still belonged to the Shire, and the hobbit wanted to see Rivendell again before he returned home. So Thorin provided him and Gandalf with a horse and a pony, each laden with supplies and Bilbo's share of the treasure. Bilbo gave each of the company a warm hug before stopping at Thorin and holding out his hand. Thorin laughed and pulled Bilbo roughly into a hug, making the poor hobbit gasp for breath.
"Thank you, my dear Bilbo, for helping us succeed in this quest," Thorin said, tears almost (almost) threatening to surface.
Bilbo chuckled. "You are most welcome, my friend." The hobbit waved goodbye and him and the wizard set off from Erebor, their path leading them back to Bilbo's rightful place at his warm hearth.
After Bilbo had long since gone, Kili turned to his brother.
"So," he said lightly, "We still haven't learned everything there is to know about this huge mountain. Want to keep exploring? See if we find any more rare weapons?"
Fili smiled mischievously, and the two of them ran off into the mountain, heading only they knew where.