No one ever told Merlin he was a liar.

He was, of course, his mouth spewed falsities and half-truths and nothing but dust half the time. There was no substance, no goodness, nothing other than another fact or figure that had nothing to do with life or reality, only made real by his mind.

No one ever called him a liar, though.

They would believe anything, people would, anything that touched his lips. There was not a falsehood they wouldn't repeat, even if every fact pointed to the contrary. They would believe every word he said.

No matter what.

So Merlin did lie, and often, because he would never be caught, could never be caught. Lying was second nature to him, and the truth was a far-off concept so out of his reach that he could hardly comprehend it. He never wanted to tell the truth, never wanted people to know that he felt a cold expanse of nothing, that he reeked of failure and confusion.

It was best that they just kept believing his lies – like magic, they always took his word as gospel.

Merlin never had a problem with it.

Not until Arthur.

"You never have anything to eat in this house," Arthur sighed dramatically, slamming the door to the refrigerator shut with a loud thump. Merlin, from his spot laying lackadaisically on the worn couch, turned his head just in time to see Arthur throwing himself over the back end of the old garage-sale purchase and half onto Merlin's lap. With a surprised oof, Merlin laughed.

"Get off of me," he said, shoving Arthur's feet, but Arthur refused to cooperate, instead digging his elbow into Merlin's stomach.

"Do you want me to stay the night?" Arthur asked, somewhat casual but still with that underlying racing that all new relationships had – Merlin had never even considered a real relationship, with commitment or trust before now. "'Cause if not I'm leaving. There's a Manchester United game on tonight."

"Manchester's shit," Merlin responded automatically. "And of course I want you to stay the night."

He wasn't lying, he wasn't even close to lying, but Arthur's face split into a grin that would make the sun shine. With an uncomfortable and guilty thump, Merlin realized Arthur would have believed him even if the words had been a lie.

He was just like the rest of them, after all.

"I love you," Merlin told Arthur six months later, after too many believed lies and too many believed truths. When Arthur leaned in to kiss him, Merlin wondered if Arthur only had faith in Merlin because of his gift for lies, or if he would love Merlin even without it.

"What do you mean – People believe your lies?"

"I tell someone something – anything – and they'll believe me, no matter what."

Merlin had never told anyone this truth, not ever before. Arthur's eyes regarded him with frightened, nervous, angry energy – but not confusion or suspicion. Because Arthur believed him.

"You mean like – like magic, or something?"

"Or something."

"I don't believe in magic – but I believe you. Oh, God, I believe you," Arthur swallowed visibly, eyes widening and skin going white. Merlin wanted to reach out, comfort, hold, but he knew that the reception would not be pleasant. "Why do you I believe you?"

"Because you have to," Merlin said quietly, screwing his eyes shut and wishing fervently that they didn't have to have this conversation, that he was entirely ordinary. "I'm so sorry, Arthur."

"Are you?" Arthur whispered, reaching a hand out and steadying himself on the coffee table. "I think you are, but I can't – If this is the truth, then how can I know that you're telling it?"

Merlin wished again, just in case. "You can't."

"Oh, God."

"Arthur, this doesn't – I love you, I would never lie to you," Merlin tried, desperation heavy in his voice at the sight of Arthur visibly holding back tears. "You're the only – You mean everything to me."

Silence reigned for seconds that felt like sunlit days before it was interrupted by a bitter, broken laugh. "There isn't a single part of me that doesn't believe that with all my heart. But you could be lying and I wouldn't know the difference, would I?"

"No," Merlin whispered, voice cracking in shame. "No, no, you wouldn't."

Arthur stayed, but he wouldn't look Merlin in the eye for weeks. Merlin slept in the other room. Arthur hardly came home.

"Can I – Arthur, can I –"

Merlin felt safe enough to ask after a month of stony quiet, but he wavered in the doorway. The lights were all dim and he could barely make out Arthur's figure in the bed. He expected a rejection out of hand, but Arthur didn't concede to the expectation.

"Fine."

Though his voice wasn't particularly encouraging, Merlin took what he could get. He tentatively made his way across the room, lifted the covers as gingerly as he could before winding himself around Arthur's middle, skin hot and flushed against his own. Merlin pressed a kiss to the back of Arthur's neck – they hadn't done much of anything since he had told him his secret. Their friends were highly concerned; whispers about their impending break-up were everywhere. Merlin hoped more than anything that they wouldn't come true.

"I'm not forgiving you," Arthur said quietly. "You didn't tell me for a year. And I still don't know if I trust you or not."

"Understandable," Merlin held tighter.

Arthur sighed into the touch. "Just don't – don't tell me things, okay?"

"I'll try," Merlin said, then realized he was already breaking the rule. "I mean – I'll – fuck – You know – Fuck."

Arthur snorted. Merlin buried his head in Arthur's hair. "Just once more before I'm done – I love you."

Arthur's muscles tightened almost imperceptibly. "I wish I knew if I really believed it."

Later, in a drowsy half-sleep, Merlin heard "I love you, too," but he was certain he imagined it.

"Merlin?" a finger snapped in his face. "You awake in there?"

"Uh, yeah, sorry," Merlin broke out of a daze as Gwen looked expectantly at him across the table in their most frequented table. She had insisted on meeting for lunch that day with exciting news about her and Morgana's relationship. Merlin was happy for her, he really was, but he had slept about an hour and half in total last night, tossing and turning and worrying incessantly. Arthur was just as bad off as him, having been in the same way, and was next to him downing a cup of coffee in record time.

"Honestly, have you heard half of what I've said?" Gwen shook her head, annoyed and impatient.

Merlin responded with an earnest and untrue "Of course, Gwen."

Gwen nodded, satisfied and smiling even though it was blatantly obvious that Merlin wasn't telling the truth.

Arthur, on the other hand, snorted into his drink. "Liar."

Merlin's heart stuttered to a stop.

He let out a breath he didn't know he was holding when he turned to face Arthur, his own look of awe and excitement reflected in crystal eyes. Arthur would have never – he would have had no choice, none at all, just like Gwen, but to believe anything Merlin said.

But he had called Merlin a liar.

"What's going on – ?" Gwen began, confusion present, but Merlin cut her off.

"Gwen, please, just – just listen to me for a second," Merlin said, gasping for breath as he reached across the table and took her head in both of his hands. He didn't care how disturbed or confused she was, though, not right now.

"I love Arthur," he told her, looking her dead in the eye. "I love him more than anything in the world. He means more than anything to me. And on my life, I would never, ever lie to him."

Anything Gwen had to say on the matter was blown away by Arthur launching himself onto Merlin's side, nearly into his lap, and kissing the living the daylights out of him. They didn't come up for air for nearly a minute, a minute in which there were several whoops and whistles, but they were muted by the blood thundering in Merlin's head. He had never felt more wonderful, more relieved, and more honest.

"I believed you, I believed you," Arthur said as they finally broke apart.

"Love you, love him," Merlin stammered out, not sure if he was talking to Arthur or Gwen or himself. "So much, Arthur, so much. Please – You know now, right? You know?"

Arthur answered by kissing him again.