Work Text:
“I thought I knew you.”
And really, that’s what he’s stuck on. Merlin knows Arthur to his bones, and Arthur had –foolishly- thought he’d had the same privilege with Merlin. Despite the buffoonery and general foolishness, Merlin is a private person and Arthur has worked hard to collect all the pieces of Merlin into a whole. He’s met Merlin’s mother, seen where he grew up, and met his childhood friend –a disaster he doesn’t like to think about, but now sees in a new light. He’s trained Merlin with a sword, watched him become a marginally competent servant, and an excellent friend.
All those pieces and now it turns out he knows nothing, and it hurts, somewhere deep in his chest –not his heart, maybe his lungs or spleen or something. He spends the trip distracting himself from the pain of his mortal wound by watching Merlin, trying to remember every time there might have been even a hint of Merlin having magic. He comes up with dozens, more even, odd moments, all those things that didn’t quite make sense or ring true, all those times he’d simply chalked up to Merlin being Merlin. He doesn’t know what bothers him more: that he didn’t figure it out or that Merlin didn’t tell him.
Because Merlin had his trust, more than even Gwen, and it turns out that Merlin never truly trusted him.
And the worst part of all is that he can’t even tell Merlin he was wrong not to trust him. Arthur can’t tell him that he wouldn’t have had him executed and perhaps that burns worst of all. That he never had Merlin’s trust because he didn’t deserve it.
Watching Merlin do magic is like watching an entirely different person. Or maybe it’s that Arthur is a different person, now that he knows. And maybe that’s what Merlin was trying to protect him from.
When this is over, when Merlin has saved him using magic, they'll have it out, finally. Arthur will shout and throw things and insult Merlin's intelligence and Merlin will do it all right back and maybe Arthur will stop feeling like the ground has crumbled away beneath his feet.
When this is over.