The Uneasy feeling continued, and though Thorin could not pinpoint its root, now that he had acknowledged it he could not ignore it any longer. He began watching Kili more closely, and instead of dispelling his worries, what he saw began to worry him. Kili was still so young, barely eight years old, but he carried himself like he had a great weight pressing down on him. It may just have been the separation from his brother, but Thorin knew that was not all it was. And the more he looked, the more he saw, and he struggled to find the words to ask Kili about it.
Every attempt had met the same resigned eyes and slumped shoulders and muttered agreement to whatever he said. If he tried to spend some extra time with him, trying to close the distance that had opened up between them, he was met with open confusion and just a hint of reluctance, like his nephew wasn't enturely sure of his intentions. So Thorin had stopped that, withdrew back into the role of the watcher once more.
Kili was still behaving oddly in his training, wielding his weapons clumsily, dropping them on first hit and looking utterly crestfallen if he was praised for completing a training set correctly. So completely different from the little boy who had chattered to him non stop when he had started his training, so pleased to be learning so many new things. What had changed since then? When had Kili stopped being himself.
It made Thorin feel a little sick to realise that he didn't know.
But he watched, and he saw, and eventually he understood.
Kili carried a book with him always, kept it tucked under his arm, or shoved under his legs when he needed his arms free, or if it was not with him, it was hidden away somewhere Thorin had not been able to find. If Thorin asked about it he was told it was "Nothing" or "Just a book". And each vague answer told Thorin more than Kili probably meant to. Because if he ever had ocassion to catch Kili reading it, his face was scrunched into a feirce concentration and was completely intent on the words on the page.
What exactly a book had to do with Kili deciding that he didn't want to keep training Thorin wasn't sure, but he was determined to find out. But the only place he did not go to search for the book was in Kili's room, because it was the room he shared with Fili, and Thorin did not want to see how his whirlwind of a nephew had taken over the entire room, it would be just another stark reminder of Fili's absence.
So he made up his mind to ask for the book, and was surprised at just how quickly the whole thing had escalated to shouting, with Kili clutching the book to his chest, red faced and angry, and somehow it had devolved into Kili screaming about how terrible he had been since Fili had been gone, and how he wished Fili would stop writing, ending with a tearful "I wish it had been me who'd gone away! Maybe you'd be happy then!"
And Thorin, whose own temper had been steadily rising, fuelled not only by Kili's words, but his own guilt and denial of, exploded, and he only barely stopped himself from growling out. "I wish it had been you too. fifty years would have been too short!" but something that felt suspiciously like Fili held that thought in an iron grip and didn't let it loose. Instead his hand snapped out.
And there was a deafening silence followed by the soft thump of that damned book onto the floor, and Kili's eyes were wide and round and bright with tears, small fingers pressing on the red mark across his cheek.
"Go to your room!" Thorin snapped, and when Kili did not move last of his anger snapped as well and he roared to be heard over the sound of his own horror at what he had done. "Go!"
And Kili did, flinching away from him and dashing back to his room.
Thorin stood, breathing hard his eyes dropped to the floor, to that book and with an inarticulate growl he kicked it aside and left the royal chambers, slamming the door behind him and went straight to the Kings Forge, feeling less of a King than a Monster, and threw himself into the metal with a ferocity he had not felt since Fili left.