Merlin had heard about the curse before he ever went to Camelot, of course, but he hadn't really been sure he believed it. The whole thing sounded far too much like the ghoulish whispers gossipmongers always liked to come up with - that Camelot's knight's cloaks were red because of all the blood they were stained with, that there were bones at the bottom of every one of Camelot's ponds, that Uther Pendragon smiled at executions. No one in Ealdor really believed that a witch had managed to curse the entirely of Camelot to "show their guilt," whatever that meant.
Will had plenty of theories, but Merlin was pretty sure Will had come up with of those on the spot.
It wasn't until he actually got there and saw the black numbers crawling up the guard's hands that he swallowed and thought, Alright. Maybe it's more than a rumor after all.
But it wasn't like he was going to kill anybody, so it wasn't like it had anything to do with him.
Then he kills Mary Collins and wakes up in the middle of the night stifling a scream because it feels like someone is pressing red hot metal into his shoulder.
When he stumbles to the window, he notices a still smoking number one pressed into his shoulder.
He's careful to keep his shirt on after that.
If they stayed on his shoulder, it wouldn't be a problem. Arthur might constantly be getting shirtless, but Merlin had more sense than that.
But as Arthur's skin showed, the numbers didn't stay there. They spread.
"It's nothing to be ashamed of," Arthur said impatiently the first time Merlin helped him undress. Merlin's eyes had caught on the seemingly endless spirals of numbers wrapping up his arms and climbing up Arthur's chest. "I earned these defending Camelot."
Arthur held his chin high and believed it for most of them.
But there were a few numbers that Merlin quickly learned to take great care not to touch.
A few numbers glimpsed on his own arms might be okay. They'd fought bandits often enough that Merlin could explain them away pretty easily.
Merlin quickly gained more than a "few" numbers.
They were always tender, the day after, but he stopped waking up for them.
He was glad. He needed the sleep.
He wondered sometimes what wiould happen when the witch died. Would her spell end? Or would it go ever onward, to the end of time?
What would her numbers look like?
He didn't even notice it, is the problem. He was so banged up anyway that he didn't notice the inflammation of his hand until it was too late, and Arthur was ignoring his breakfast tray in favor of looking at Merlin in horror.
"Merlin," he said carefully, "why is there a number on your hand?"
Merlin looked down.
He wished it was a lower number.
"You don't want to know," he said wearily, knowing full well that those words couldn't possibly be the end of it.
But Uther was dead, and Morgana was a traitor, and Agravaine was a traitor, and Arthur just - nodded.
And that was the end of it.