Arthur had been wondering for a long time about his supposed «destiny». He'd first heard of it from a druid child he'd stumbled upon in the forest one day, separated from his knights and Merlin as he was, and the little girl had gaped at him before exclaiming that he was «the Once and Future King!»
He hadn't had the heart to kill her, as while he certainly didn't trust the druids, he had at times entertained the possibility that some of them weren't all that bad either – after all, they generally kept to themselves and didn't cause any trouble, claiming to prefer healing and peace rather than the usual evil magic was used for. Besides, she was a child, and the mere thought of killing her by his own sword for something she had been born into, and wasn't even old enough to understand and therefore unable to shy away from, sickened him. She could still learn to see the error of her ways, as long as he gave her the chance to. And so, as for all her druidic clothing she was still a child alone in a forest, he had opted to help her find someone to take care of her.
As they went, she had gone from staring at him in awe to chattering inanely about how he was this Once and Future King that would bring back magic to the kingdom and that he supposedly had a protector called Emrys who possessed magic and spent most of his free time saving Arthur's life, all the while giving him her opinion on the many pieces of absolute rubbish she spouted. Mostly, her meaning was that basically everything mentioned was «cool».
After that, Arthur hadn't thought about the little druid girl and her talk about destiny for a while. He hadn't really thought anything of the armful of babble at the time, as it had simply seemed much too ridiculous to be taken seriously. Firstly, because she was a child, easily excitable and probably unused to being in the presence of royalty. How she had recognized him was a bit of a mystery, as while he was wearing chainmail he could easily have come off as just another knight, but he figured his face wasn't that uncommon to have seen before, so he didn't think much of it. Secondly, she had said there was a sorcerer protecting Arthur. Arthur! Like a sorcerer would ever protect him. No, not even a practitioner of magic would be that stupid. And thirdly, because she was quite clearly convinced he was going to bring back magic to the land at some point. Err, yeah, sorry to disappoint, but no.
Not to mention, she had been happily informing him of these things in an unconcerned, of-course-it's-true way that suggested she hadn't even considered it could be wrong. Probably a bedtime story taken a little too seriously.
But then… slowly, things had started to crop up. Merlin calling him the Once and Future King, for example. Arthur had almost called him on it, before thinking better of it and shrugging it off as a coincidence. Morgana, telling him that «Not even Emrys can save you now». All those little tidbits and hints slowly making him reconsider his earlier rejection of the druid child's words. And then, it made sense.
All those times he had faced something he should not have come back from alive and yet miraculously made it, all those times Gaius had claimed that magic was the only solution to a problem only to – somehow – be proven incorrect – it all came down to this.
Emrys had been there. Emrys had been protecting him, making sure he would survive long enough to fulfill his destiny. And for him to always know what was going on, he had to be close by. He had to be someone close to Arthur, someone who had always been there by his side… And Arthur knew exactly who it was.
After all, there weren't that many possibilities. Who was it that had shown him such astounding loyalty and will to keep him alive? Who had been there by his side, always making it out of yet another battle despite the odds being beyond hopeless? Who had never, never strayed from his side and believed in him no matter what?
Who had even been saved by druids, once?
The answer was obvious. It was Sir Leon.