three facts
It wasn't until they were back in Camelot and Arthur had shot him a Look from under his eyelashes, and said, quietly and brusquely, but not at all unkindly, "You're free to do as you will till you feel – ready to attend to your duties again," which Merlin had understood to mean I really am sorry for your loss and also, I'm glad you came back to Camelot with us – with me, so he had smiled back tiredly and said, "I'll be there tomorrow morning, bright and early as always," and Arthur's eyes had softened with something incredulous and dangerously close to hope before he'd snorted, looked away and said, still quietly, "Suit yourself, though if I find you staggering around the castle like a half-drunk loon, I'm ordering you off duty," and then louder, in his most annoyingly arrogant voice, "And get Gaius to look at those saddle sores, won't you, Merlin," which had only made Merlin paste on his most obnoxious grin and say in response, "Of course, sire. I'll be sure to pass on what tincture he recommends," and he'd gotten a glimpse of Arthur's lips tilting east-north-east at that, before he'd taken the reins of both their horses and began leading them to the stables and that was really meant to be Merlin's job, so – and it wasn't until all of this, that Merlin became positive of three facts:
One: that Merlin's home was no longer Ealdor, and perhaps it hadn't been, for the longest time. Home was no longer harsh winters and sweltering, brilliant summers, no longer his mother's worried hands smoothing back his fringe, trying to teach him a precaution that never really lasted when it came to Arthur, no longer lying in heather fields chewing milkweed with Will, whiling away the long summer days and not talking about the spaces between them, ever growing. Ealdor was the home of his mother, and the home of his childhood, but it was Merlin's home no longer. The realization was only a cool shock, an obvious conclusion to draw when Will had asked him whether he valued Arthur over Ealdor and it hadn't even been a decision, though it should've been: only the uncomfortable truth, a cold weight at the bottom of his stomach.
Home was bearing the itch of a heavy and ridiculous-looking weight on top of his head, voluntarily, and forgetting it completely when Arthur's fingers curled more steadily around his goblet and he huffed a laugh, looking more at ease than he had for weeks after the business with the diplomat from Mercia dead with a knight's arrow in his back and Arthur being blamed and war only being narrowly skirted, again. Merlin had felt a small burst of pride at that, for being the only one to make Arthur open up after the entire mess; a crick in the neck and a few uncomfortable hours little price to pay to see Arthur laughing again.
Home was waking up cold and wet and with a throbbing pain in his chest, and remembering oh right, evil sorcerer and the feel of Arthur's tunic under his fingers as Merlin had shoved him aside. "Idiot," Arthur's voice said, thickly, and Merlin had tilted his head up, surprised to realize that it was resting in Arthur's lap.
"Right, because I'm the idiot when you're the one who decided to go on this ridiculous hunting trip, alone, when you knew perfectly well there was a sorcerer bent on having your head on the loose, you enormous prat. Sire." Merlin's voice was scratchy, and the chill of the forest floor had begun to make him shiver. There was no answering jibe from Arthur though: he only sighed and dropped his head, before catching Merlin's eyes, looking strangely serious and wretched and desperately unsure.
The moment passed quickly though, and Arthur had just ducked his head and called him an idiot, again, the thin line of a smile spreading across his lips, before bundling Merlin's arms and legs and seventeen elbows into his lap amidst Merlin's half-hearted protests. "Shut up, Merlin," Arthur drawled, sounding more and more like himself, and had draped his cloak over the both of them.
Oh, thought Merlin, and had rested his head against Arthur's chest. This is quite nice.
Home was sitting together like that, for a while. (And the day after, when Merlin had managed to somehow singlehandedly drop every breakable article in Arthur's chambers at least twice and Arthur had cuffed him across the head so lightly that it almost felt fond, before sending him to muck out the stables and scrub the chamber pots and take the dogs out for a run – around the entire castle – and polish his armour – that was home too.)
Home was goblets and flowers, cold lakes and warm hands, dragons and destiny. Home was shared smiles, easy banter, affection disguised as casual derision. Home had followed him to a village perched on the edge of nowhere and defended it like it meant the world. Home was – and well, it was almost too ridiculous to bear thinking about, really, that Merlin could find someone that utterly obnoxious, and still know he'd lay his life down without a second thought to keep them alive – home was with Arthur.
Two: that home was where he fit in. Home was where he belonged.
And three: that if they were back in Ealdor and lying on Hunith's stone floor (and Will was still alive, thought Merlin, stomach lurching painfully) and Arthur asked him once again whether he'd found somewhere he fit in, somewhere he felt he belonged, Merlin's admittedly dysfunctional brain-to-mouth filter would just switch off completely and he'd probably say something hideously girly and also embarrassingly true like "Yes," and also, "It's with you."