Merlin's known not to talk about his friend Arthur ever since his mum cradled his face and told him of the stark black-and-white difference between reality and the magic Merlin likes to gabber about.
Arthur is his friend. Arthur isn't always there, but whenever Merlin is alone or in pain, he closes his eyes, shutting them tight, and reopens them to find the odd man wearing funny clothes and a silly crown sitting beside him, smiling and reaching out towards his wound or his heart.
"And how are you today, my sorcerer?" is always the first thing he says. Merlin wishes his fingers could really touch the blood oozing from the scratch he got in the park, or sink right through his chest to ease the constriction in his heart. But Arthur's shimmering, flickering fingers always stop millimetres away from Merlin's skin and they both look at each other with confusion, resignation.
"It's my birthday today," Merlin tells Arthur one afternoon when a summer cold has confined Merlin to his bed and everyone is outside on the lawn celebrating on his behalf.
"Happy birthday," Arthur says, still wearing those strange clothes that belong in a low-budget medieval movie. To Merlin, though, he looks like a superstar. He always has. So cool, even in those stupid clothes and the crown that Merlin's tried to tug off many times, with Arthur's laughter in the background, but which won't budge. "How old are you now?"
"Ten years old," Merlin says. Arthur smiles widely.
"A special number," he says. "Requires a special celebration."
And no matter how many times Merlin's mum cries and tells him magic doesn't exist even as Arthur stands next to her, Merlin can never believe her because Arthur waves his hand and suddenly Merlin is on a shabby old cot in a dusty old room. Merlin sits up and looks around. The air smells musty and stale and reminds Merlin of all the things Mum always puts in her tea and in her homemade herbal paste. He can't bear it.
"Take me back," Merlin says, anxious all of a sudden. He doesn't like this. He doesn't like it but he can't understand why. Arthur nods and in a blink of an eye they're back in Merlin's bedroom, hot sunlight warming Merlin's face and laughter pouring in from the open window.
"Did you not enjoy being transported?" Arthur asks, genuine hesitation on his face. Merlin shakes his head.
"I felt ill," he confesses.
"I'm sorry," Arthur says quietly.
"C'mon, you can play cards with me." Merlin doesn't like to see his friend sad.
There's obviously something unnatural about having a man that looks like he's thirty be Merlin's friend, but Merlin realised at a very early age that Arthur grew no older with him. He was magic, after all. Imaginary. He would always be thirty. He'd been thirty when he'd calmed an infant Merlin down so his mother could sleep through the night, he'd been thirty when he'd saved two-year-old Merlin from drowning in the sea. When he'd learned to write the alphabet alongside Merlin, mimicking Merlin's hand movements and the tongue poking out of the corner of his mouth.
"Why me?" Merlin asks three years later, when Arthur is lounging an inch above the mattress and Merlin, his back to the bed, is flicking through a textbook at his desk. "Why are you haunting me?"
"I'm not a ghost, Merlin," Arthur replies, amused, though his lit form starts guttering again. "I'm just… Arthur, your intangible friend. You dreamt me into existence with your ridiculously powerful magic."
"Magic isn't real," Merlin mutters, sullen. "I'm probably just mental."
(He can't feel the fingers brushing over his nape, nor can see he see the grief on his friend's face.)
"Magic is real, my sorcerer," Merlin hears after some time has passed. "Won't you believe me?"
"You don't exist," Merlin snaps, hissing the words so his mother doesn't lose another piece of her soul with a sigh. "You're just someone I made up because no one would talk to the shy kid at kindergarten."
"I've been around longer than that and you know it."
Merlin says, "Well, if I'm really magical then disappear before I turn around."
An entire minute later Merlin, strung up and terrified, glances back.
Arthur smiles at him, stretched out on the bed.
"You're too transparent. I'm never going to leave you, you know."
"You've watched enough movies with me to know that's one of the creepiest things you could've said to me," Merlin says, hiding his relief by curling into a ball on the chair and sobbing fitfully as a glittering, shimmering hand covers his without actually touching him, and strands of golden hair strike through his vision.
Arthur's always there. The next four years are hell because Arthur at least used to vanish for hourlong, daylong stretches of time before then—now he's Merlin's shadow, visible whenever Merlin searches for him, meeting his gaze with a knowing smile and a sardonic wave. Merlin goes through school, tuition, holiday trips with Arthur at his side, refusing to meet his mum's gaze or responding to her gentle prying about his childhood imaginary friend, is he still there, do you still talk to him.
But once, just once Arthur isn't around and so Merlin snatches the opportunity to huddle under the covers, slide his hand all leisurely into his shorts; he hates being a teenager constantly on edge and hates that porn won't get him off because the last time he tried Arthur suddenly appeared and snidely remarked on his preferences ("athletic blond men, Merlin?") and ruined everything and hates being fifteen, sixteen, seventeen, wanking in the shower in two minutes and feeling tetchy and dissatisfied all week. So he snatches the opportunity—hides under the covers and fondles his cock inside his shorts, working himself with both hands slow and hard, leaking as he pulls a knee back to press a finger against his hole, light and circling, can't hold back the gasps and the, unh, Arthur, Arthur, oh, Arthur—the blankets slide off his head as he rocks in his bed, but he keeps his eyes closed.
He has to keep his eyes closed as he jerks his hips up to push the shorts down, down, off his legs, two fingers in and he needs to be wetter, slavers lavishly on the other hand and leaves his weeping cock alone to just, aah, God, Arthur—
His eyes snap open and Arthur's on top of him, beautiful and golden, an inch and crown off, and he's looking down at Merlin's nose with a pained, guilty frown and his hands are on the blanket on top of Merlin's cock, squeezing but not squeezing and his mouth is parted right over Merlin's in a poor, brilliant imitation of a messy, ardent kiss, and Merlin comes and comes and comes.
"What are you," Merlin whispers, ten years later when the embarrassment has mostly died down to be replaced by hours and hours of learning his own body so Arthur can learn it too.
"I don't think you're going to find out, my sorcerer."
"Am I—"
"Probably."
"Magic?"
"Fiction," Arthur says, though it's as if he's dying inside just saying it. Merlin's exhale is wavery.
Arthur glances at Merlin sheltered in his disgusting blanket and bites his lip and starts fading away for the first time in a decade but Merlin leaps at him, wild and naked and desperate. Arthur's arm, in a tunic sleeve, Merlin knows now, flares back into existent non-existence.
"You said you won't ever leave me."
Arthur looks at him strangely. "Merlin."
"You can't. I don't care if I am cra—"
"I lied. You're not. You're the only one in the world who'll ever see—"
"Why me. Why me?"
"Because I've loved you ever since the first time I saw you," Arthur whispers. "Because I abandoned you the first time and swore to the gods I'd never leave you again and the gods granted me my heart's desire."
Merlin closes his eyes. It's his twenty-seventh birthday today and his family and friends've been sent off on a trip to Spain to live it up on his behalf. His mum won't look at him anymore.
"Twenty-seven isn't a special number," Merlin mumbles into Arthur's mouth, wishing he could be warmed by Arthur's breath. "But can the celebration be special anyway?"
"Of course," Arthur mumbles in answer.
Merlin lets Arthur take him back to that forgotten old cot in a forgotten old castle, back to wherever he wants.
He doesn't feel ill this time. He doesn't feel anything except the trace of Arthur's hand sure in his.