A/N: It has been many, many years since I have written anything LotR related, and I'll be the first to admit that I'm a tad (or a lot?) rusty. I did, however, do some researching and re-reading before diving into this endeavor, though it in no way makes me faultless. I've written this story with a mixture of book and movie cannon (obviously, as Tauriel doesn't exist in the books and Azog was killed long before the events in The Hobbit). I'm aware that many LotR/Hobbit fans were outraged by the not-so-subtle love story between Tauriel/Kíli, but I myself loved it and thought perhaps I might contribute a story centered, as believably as possible, on what that might possibly lead to.

Description: Tauriel saves Kili's life during the Battle of the Five Armies and alters the course of history, forever. (Highlights the years between The Hobbit and the Lord of the Rings Trilogy).

Disclaimer: I own neither the works of Tolkien nor the creative prowess of Peter Jackson, so take pity.

EDIT 1/04/2015: Many thanks to Austin B. who took the time to beta this chapter and those that follow. Huzzah! A beta for me at laaaaast.

The Heir Apparent

Chapter One: The Fall of Durin's Line

Oh, misty eye of the mountain below

Keep careful watch of my brothers' souls

And should the sky be filled with fire and smoke

Keep watching over Durin's sons.

-I See Fire,

Ed Sheeran

23 November, 2941 TA

Tauriel was no stranger to death.

Her two hundred years as Captain of the Guard had shown her the fragility of even an elven life, but she had never imagined she'd witness it at such magnitude or cruelty. The very air was poisoned with anguish and loss and her lungs burned with each shuddering breath she drew. Wielding bow, arrow and swords, she pressed her way through the host of Goblins, Wargs, and Orcs toward the small, lethal company of dwarves as they cut a path from the Gate of Erebor. They were nearing the ground Azog and Bolg held, the two Orcs surrounded by their personal, well armored guard, and fear leapt into her heart. She was not going to reach them in time.

Her world became a blur of grotesque faces awash in black blood and harried by shrill cries of pain and death. She fought harder and more fiercely than even she had believed possible and later, after the battle had been won, many would speak in hushed, reverent voices of the She-Elf who had felled every goblin who came before her, leaving a river of death in her wake. She would remember very little of it save for the moment she broke free of the main host and watched Thorin as he fell. Her world narrowed and slowed as she caught sight of a familiar black haired archer with his elder brother at his side as they faced down an impenetrable wall of Warg-mounted Goblins. She watched, transfixed, as the brothers stood resolutely over the prone form of their fallen kinsmen, swords raised in stubborn defiance.

Curse the foolishness of dwarves, she thought and leapt forward. She reached behind her to take another arrow, intent on saving the two brothers if she could, and felt only empty air. Her heart stopped and her steps faltered; she was too far away to be of any use hand to hand and she watched helplessly as Fíli took a blow to his midsection and stumbled. Despite the distance, Tauriel could hear Kíli's cry of outrage and grief. He threw himself wildly into the line of Goblins in a rage of flashing steel.

I did not save him only to watch him die.

Determined, she took quick survey of the area around her. Men, elves and dwarves fought in close proximity but they took no notice of her, engrossed in their own battles and fears. She caught sight of an elven arrow, gold tipped and finely made, protruding from the gut of a Goblin a few feet away and judged it her best and only hope. Leaping over several corpses, some of them familiar to her, she yanked and twisted the arrow free of the vile beast and with no hesitation she raced across the blood soaked earth to place herself in range. Pushing her fears, doubts, and heart aside, cool calculation took control. Kíli was holding his own but he would not last. He was a skilled, hardy warrior, perhaps more so than she might have anticipated, but help would not reach him in time. She was his only hope and she had only the one arrow.

He stumbled when she was only barely in range and Tauriel knew, as a Goblin raised a crude sword over his bulbous head and Kíli fumbled for his own weapon, that this was her only chance. Dancing away from the blade of a charging Goblin, heedless of her own safety, she stopped dead and took aim. She breathed, once, she breathed twice, and she fired, setting her arrow free with all her hopes and wishes and deepest, largely unrealized, feelings along with it. Like a miracle, the arrow found its mark through the creature's eye and Kíli rolled to avoid the falling, armor-heavy body, rising quickly to his feet with sword in hand. He turned toward her in surprise and their eyes met across the bloody chaos. Tauriel experience a moment of pure clarity unlike any she had experienced prior and it shook her down to her very core.

I love him and it will be the ruin of me.

But they were not out of danger yet and Kíli obviously refused to leave his brother and Uncle's side. A line of enemies stood between she and the young dwarf prince and she drew her knives with deadly purpose. She was alone, with no one at her back, and she knew she had placed herself in a dangerous, possibly deadly position. At least, she reasoned, she could take as many of the foul beasts with her as she could. And maybe, by the grace of the Eldar, she had managed to save Kíli's life. Again.

Suddenly, from somewhere behind, she heard a roar so fierce and terrible she fell immobile in its echo. The horde parted in degrees and the Goblins around and before her faltered, many fleeing. Wide eyed and rooted, Tauriel watched as a massive bear came barreling toward her, shredding Goblins with teeth and claw, a dreadful blood thirst in its black eyes.

"Tauriel!" came a voice, familiar and fierce, "Move!"

With a gasping cry, she darted and rolled away from the creature with a mere hand's breath to spare. When she rose, Legolas was at her side, hair disheveled and streaks of blood, red and black, marring his beautiful mithril armor. He held one of his long daggers in hand; it was black with blood.

"Are you alright?" He asked, his tone tight and his face hard. He wore his father's eyes, cold and calculating, and a chill took her. Taruiel felt faint as she nodded and took his proffered hand, rising shakily to her feet. The fight in her momentarily subdued, she wearily watched the path the great bear carved and felt sick inside as it neared where Thorin had fallen; where Kíli, whom she could no longer see, had last stood.

"The King Under the Mountain has fallen," she murmured and released Legolas's hand.

"Then he met the end he deserved," Legolas replied, tone harsh and void of emotion. Tauriel hadn't the strength to argue and again followed with her eyes the path the bear had created in hopes of finding Kíli still alive somewhere in the wreckage. Legolas stopped her with a firm hand on her shoulder.

"The dwarf prince is dead, Tauriel, do not follow after him."

Anger flared as the battle around them turned, at last, in their favor, and she shrugged off his hand violently, facing him with snapping eyes.

"Then I shall mourn his loss and that of his kinsmen, for they were beings worthy of remembrance and honor," she said, though in her heart she could not accept that Kíli was, in fact, dead. Legolas looked stunned, hurt, and perhaps even betrayed, and she turned her back to him.

As she moved up the slight rise toward where she had seen Kíli last, humans, dwarves and elves alike fell in line beside her, eager to route the remaining Goblins as they retreated. Tauriel could not have cared less. Many lives had already been lost and she was not eager to watch the loss of more. She crested the hill and discovered the body of Thorin was gone with the massive bear nowhere in sight. Fíli, however, remained where he had fallen. Turning, she spotted an achingly familiar blue cloak and dark head motionless on the ground a yard away. She looked back briefly to the fallen dwarf before her as a spreading numbness swept through her limbs. Fíli's eyes were closed and the blood from his stomach wound had long since stopped flowing. His once cheery face was pale and flecked with blood and dirt, his broad chest still.

"Go in peace, young prince," she murmured softly in Sindarin and moved away, leaden feet drawing her toward the prone form of Fíli's younger brother.

She fell boneless to her knees beside Kíli, heedless of the blood and grime and dimly aware she was crying. With trembling hands she reached out and rolled him gently onto his back. His responding groan was perhaps the most joyous sound she had ever heard and her heart stuttered in her chest.

"Kíli…" she breathed and watched as his eyes fluttered and opened. His face was pale, his hair tangled and matted. There was a thin trail of blood trickling from his nose and his dark blue eyes seemed dazed, but, miraculously, he smiled. She took a few deep breaths, her relief and hope so acute, they stung.

"I knew you would find me, you're… always saving me." He reached out his hand, large fingers stained and dirty, and touched her cheek in reverence. She covered his hand with hers and they stayed like that for several timeless moments before sudden grief darkened his gaze.

"Thorin… Fíli…"

Tauriel winced and reached out to smooth the hair away from his face with an unsteady hand. She spoke softly, carefully, "Thorin is gone. Taken, I expect, by the Skin Changer. He may yet be alive. F-Fíli…" she trailed off, at a loss for what to say. Grief took Kíli and he lurched gracelessly to his feet as she watched helplessly, unable to stop him. He stumbled toward his brother's body and fell across his chest with heavy, weeping sobs.

Another of his company, the one they called Balin, came to her side bearing axe and blade, brilliant in the armor of his people. She looked up at his aged faced and she saw grief and loss in the old dwarf's gaze. They said nothing as the battle died down and dissipated around them, they could only silently watch Kíli's grief and reflect on their own.

Tauriel found Legolas that evening as the sun set bloodily behind distant mountains. He sat silently and alone around the fire outside his father's great tent. A very dire meeting was taking place within, one she suspected Kíli was a part of. Stifling a groan, every muscle in her body screaming in protest, she sat beside him.

"You fought bravely today, Tauriel," Legolas said eventually, not looking at her. She watched the flames dance in his dark eyes and gleam red in his golden hair with a pang of sorrow. Did he care for her as King Thranduil had said? He was still the most beautiful elf she had ever seen and her heart ached. There had been a time, not so long ago, that she had believed herself in love with Legolas, but she had known it was a match that was never to be made. She found it ironic that the next person she had fallen in love with was a dwarf and much further beyond her reach than any elf might ever have been.

"As did you, my Prince," she said kindly and he glanced briefly at her face. An awkwardness fell between them which had not existed before the fateful day they had captured the company of Thorin Oakenshield and she mourned its lost. She felt she was losing an important friendship but seemed ill equipped to save it.

There was the rustle of cloth as the tent flap was lifted and they both turned to find the daunting visage of Dáin Ironfoot, Chieftain of the Ironhills, surveying them critically. Tauriel has heard many tales of the dwarf's deeds but had never seen him in person. He seemed as hard and unflinching as stone, with wild gray hair and dented armor. He stepped gruffly aside, hardly sparing either elf a glance, and Balin followed behind him. The old dwarf had been divested of his armor and was once more the humble diplomat in robes of fur and silk. His face was a mask of stoic grief and he seemed aged many more years since last she had seen him.

He met Tauriel's gaze and said, "King Thorin has died as has his nephew, and heir, Prince Fíli."

Now Balin moved aside and a figure, taller than either of the other dwarves before him, moved slowly into the firelight and Tauriel resisted the urge to rush forward. Kíli's face was pale, drawn and lifeless. Gone was the carefree dwarf she had met, who'd flirted and jested, he seemed only a shadow of himself. Tauriel had never seen such grief or such sorrow and her very being ached with the pain of it. Had she the power, she would have taken his pain and born it herself.

"I give you," said Balin, in a voice that trembled, "Kíli, son of Fínor, King… Under the Mountain."