He saw the limp form of his brother on the ground after falling from a tree he wasn't supposed to climb and ran to his uncle in the nearby forge, desperate for help, feeling guilty. Thorin had charged him with watching over Kíli, as always since their mother had passed away some years ago, but it was so hard, his brother seemed to be always ready to get into trouble, so prone to disaster, that everything he did was not enough to keep his little brother out of trouble. None told him his brother would be in a lot more trouble if it weren't for him.
But there were his uncle's eyes, full of worry and care, running to his brother but never letting go his hand, bringing him along, not ever leaving him alone. So was his uncle.
He had to speak absurdly fast to explain his uncle the burglar had been stolen by the trolls, no pun intended, and that they had to rescue him right away, and that Kíli had waited there to act any desperate attempt to keep their burglar alive if needed, but they had to hurry now! The wide eyes of his uncle whilst he shouted orders around were frantic as he reminded they had been when Kíli fell from the tree, half a century ago. His strong and wordless hand on his shoulder was everything he needed to feel safe and ready for any battle. So was his uncle.
His shout echoed in the valley as the eagle swept down with his uncle in its talons, the dwarf who had risen him as a father limp form making him shiver with fear. It should not be this way, it should not be him to see his uncle fail, to see his uncle fall, it should not be him to fear for his death in battle. He should see his uncle die as the rightful King Under the Mountain, old and battered, but still strong of will and proud of having brought his people back to their rightful home. But there, then, in the midst of the wind, borne on the wings of down, it was too much on him. He saw his uncle fall, and not to stir afterwards. If his uncle died then… it would be everything on him. The burden of Thorin's Halls in the Blue Mountains, and, even worse, the fate of the quest to retake Erebor. Thorin could not die. He was not ready for it.
It took some minutes after both his uncle and a wizard came down from eagles to Thorin to stand up and squeeze his hand in assurance that everything would be all right, even in a way none of the surrounding members of the Company would notice it. No words directed at him, but he knew, he had been risen by him, he knew his uncle would be all right. And it gave him peace. He knew his uncle felt pain, and that he worried. But that he would lead on anyway. So was his uncle.
He saw a group of orcs gather around his uncle as others of them made an effort to keep his personal guard, his companions, his family, away from the fray. It was treacherous, insidious, unfair. Disgusting.
But his shout had been worthy, it had drawn the attention of the Company, who struggled to reach their leader, their friend, their brother, their king.
His shout had been a disaster, as his little brother had heard it and dived into the fray, arrows singing from his bow until…then his own double swords were having so much work that he didn't see… then his falchions had a moment of rest only for him to see… what no one should have to see…
It was clear for him to see. The arrows stuck in his little brother's chest and abdomen had been aimed to their uncle, and this time his crazy, reckless, absurd brother had not been able to deflect all the enemy's arrows as he had done so many times before. He shielded their uncle at the price of his life. And their uncle, even if overthrown, stood up to defend his little brother's body from defiling, and for his life. In this order of priority. He had reached the same battleground and had been able to stand in front of his uncle when he felt a burning in his shoulder, and then another in his back. He looked down and felt confused by the sight of a dark jagged blade showing out of his abdomen. He heard a shriek behind him, and was able to turn around in time to see an orc fall down felled by Thorin's sword. But his own blood dripped from his belly, and he looked down at it as if it was someone else's body.
His own confused look told everything to his uncle, who knelt beside him, overthrown by his own injuries. Thorin's hurt blue eyes enveloped his own, brought him closer to his own soul, as his arms brought him closer to his chest. The pain in his guts was too much for him to ignore, and he winced.
"He is… in peace…"
His uncle's sobs were too much for him to deal with, along with his own physical pain and his certainty that his little bother was gone.
"Will we ever…?"
His unfinished question was answered some moments later, with a pair of delicate, although rough, fingers flipping his eyelids down. So was his uncle.