Arthur defined himself by two things: his title, and his adeptness with a sword.

Merlin just had magic.

But, at first, Arthur didn't know about his magic. And when he did find out, he knew that this was still Merlin. Clumsy, idiotic, bad liar, worst manservant in history Merlin, who was apparently better at deception than originally thought to be, always put him in his place, did whatever he could to help a friend in need, and apparently had a death wish he kept trying to realize by dying for Arthur. He was an idiot, really.

Merlin knew Arthur thought that, and that was alright, because he knew that Arthur was a prat: overbearing, arrogant, condescending, supercilous, a heroic clotpole and a brave and honorable dollop head who put his people before himself, didn't back down from a challenge, and didn't know how to give up.

Which would prove to be a good thing.

"Arthur," Merlin whispered urgently. "Arthur!"

The prince groaned as he opened his eyes. He let out a hiss of pain as he came around, feeling his broken arm behind him, tied to his good arm and both of Merlin's."

"What's going on?"

"I think they broke your arm."

"I can feel that, Merlin."

"Other than that…are you all right?"

"Yes, Merlin," he replied sarcastically. "Besides the fact that my arm is broken, I'm not sure where I am, and I'm tied to the most useless manservant in history, everything's great."

Merlin nodded, ignoring the tone. If he was well enough to be sarcastic, he was well enough for now. "Good."

Arthur shook his head. "Yes, Merlin. Fantastic. Now, can you get us out of here?"

Merlin began to whisper a few words before screaming in pain.

"Merlin!"

"I'm all right," he assured the prince. "I…I don't know what just happened."

Usually, Arthur would take the opportunity to sneer and teasingly point out Merlin's uselessness, but in the severity of the situation, he chose not to. He figured Merlin felt bad enough as it was.

"Merlin…we have to get out of this, but I can't move my arm. I need you to follow my instructions, even if it hurts."

"Of course, sire."

"Press your back as close to mine as possible."

"Arthur…that's going to put pressure on your arm."

The prince rolled his eyes. "Merlin! I told you it would hurt."

"I thought you meant me!"

"Merlin."

It took nearly an hour for Merlin to work the ropes as he followed Arthur's instructions. He gritted his teeth as the ropes chafed his wrists, but winced every time Arthur gasped, grunted, or squeaked in pain. That hurt Merlin infinitely more than his wrists.

"Let me do something about that arm," Merlin all but demanded once they had made their way out of the cave they woke up in. Arthur rolled his eyes as the crested a hill.

"You can't do magic on it, idiot," Arthur reminded him.

"I…I was just going to make it a sling for it."

Arthur raised an eyebrow at him, not believing the statement for a moment, but gingerly offered his arm—and dammit, that's his sword arm—to Merlin, who fashioned a sling out of his jacket.

"So…where are the men who did this to us?"

Merlin shrugged. Arthur groaned as they began the descent.

"Do we even know how to get home?"

Merlin felt a sharp pain in his head as he felt his stomach drop.

"Arthur…" he began warningly.

"They escaped!"

The voice was distant, but only slightly, and the two boys took off running when they heard the call,. After a few minutes of pursuit, the prince and his manservant skidded into a clearing, stopping as their previous captors surrounded them. In the direct center of the clearing, they stood, back to back, to face their enemies.

"Got any ideas, Sire?"

"Don't die."

"There's an idea," Merlin mumbled.

"But," Arthur continued, suddenly serious. "If we do die, we die knowing we have done everything we can to save ourselves."

Merlin considered this, then shook his head.

"No."

Arthur rolled his eyes, secretly grateful for his friend's characteristic defiance. "Merlin. I don't want to die, either, and I will try to keep us both safe, but if we do."

"No, Arthur. If we die, it won't be to protect ourselves, but to protect each other." He elbowed Arthur in his good arm. "As I've said before, my lord: I'm happy to be your servant. Until the day I die."

Arthur shook his head. "Merlin, don't…"

Not quite sure how to finish the command, Arthur trailed off. Not that Merlin was listening to him anyway. The warlock closed his eyes and inhaled. With a scream of agony, thinking of nothing but Arthur's safety, he released every bit of power he could summon.

Merlin woke to a splash cold water making his hair stick to his forehead.

"What did you do that for?" he demanded of Arthur, highly offended.

"I figured you'd had enough rest, even for the laziest servant alive."

They both heard the breath of relief in his final word, but chose to leave it at that.

"What did you do anyway?"

"Nothing," he replied honestly. "I just let the magic do it. I just thought of protecting you."

Arthur clapped him on the back of his head.

"Why was your magic hurting you?"

Merlin shrugged. "I guess they gave me something to weaken me after they knocked us out." He whispered a few words and they both saw a blue ball of light moving slowly away from them. "Whatever it was, it's worn of now. And that should lead us back to Camelot."

"Maybe you can be of use after all, Merlin! Perhaps not often, but it's more than I had thought."

"Well, if I did everything, you wouldn't have to pull your own weight. And I don't know who else can."

"Are you calling me fat again, Merlin? That's rude!"

The boys continued that way as the followed the blue light all the way home to Camelot.

When Merlin was young, before he had quite learned control of his gifts, he had been called some nasty names that sent him home crying to his mother. While wiping his tears, she told him something that had comforted him through all the teasing he had endured since.

"It doesn't matter was someone calls you, Merlin; what matters is what you answer to."

Merlin was sure, looking back, that "idiot" wasn't exactly what Hunith had meant, just as Arthur never imagined "Your Pratness" would be a title he would hear with fondness. But after almost losing the one who called him that, it was a welcome address.

Arthur may have defined himself by his title as prince, but Merlin was the one with such faith in the great king he would become that he would tell it to anyone who asked. And Merlin felt like he was magic, but it was Arthur who would make him Court Sorcerer one day. He already knew he deserved the position.

It was no title and no ability that defined them. They were two halves of the same whole, complimentary sides of the same coin. Best friends: warlock and future king.

And they defined each other.