The first time he comes back, it’s 1899 and Merlin finds him in an abandoned farmhouse in Ireland. He doesn’t know where he’s been between that point and the day Arthur’s sword struck him down, no matter how many times Merlin asks. All he remembers is darkness.
Merlin binds his magic, there and then. Mordred doesn’t try to stop him. Wherever he’s been for all this time, whatever’s happened to him, all he knows for certain is that he can’t fight anymore.
He agrees that he can’t be trusted with his magic, and he lets Merlin take it away. He wants to be redeemed, and he believes only Merlin can show him how.
It’s only after that Merlin tells him there’s no redemption. Merlin tells him that he’ll hate him forever. Merlin tells him he’s a sick, crawling thing who rid the world of Arthur and condemned them all to darkness. A base, wicked creature who ripped Merlin’s destiny from him and doomed him to an eternal half-life. Merlin tells him he will never, ever be forgiven.
Merlin’s gone mad, that much is clear. But it doesn’t mean the things he says aren’t true and so Mordred bows his head and swears fealty to Merlin forever.
Fealty is an oath for men, Merlin tells him. And Mordred is not a man, he’s a monster. The only bond he can make is that of a slave.
Mordred makes it.
After that, it’s simple. A pattern sets in. Merlin leaves, for long enough that Mordred thinks he’s never coming back and is driven mad by the thought, and then he returns.
And with him he brings pain.
Immortality is not the same for him as it is for Merlin. Merlin lives, unceasingly. Mordred dies, and is reborn. Again and again and again.
Somewhere along that never-ending cycle of life and death, Merlin comes and finds him, every time.
It always starts with a kiss, but not a gentle one. A kiss of possession, a marker of Merlin’s ownership of him. Then Mordred takes his clothes off, or Merlin rips them off for him, and he finds himself pressed against the nearest hard surface, awaiting his punishment.
It surprises him that it still hurts, after all this time. The sharp sting of the initial entry, the familiar ache of every vicious thrust, the rising panic that this time it really will break him, split him in two with agonising precision.
The pain never lessens, and he doesn’t know why. Perhaps Merlin’s made it that way with magic, or perhaps he makes it that way for himself.
After Merlin’s reached his climax, and after he’s forced Mordred to reach his own, a lesson follows.
Sometimes Merlin ties Mordred down with a wave of his hand, invisible ropes pinning his wrists and ankles to the bed, and then stands before him with golden eyes. Mutters ancient words, sacred words, to summon pain that carves and slices at Mordred; curses that boil his blood within him, that force white heat into his aching skull until he tips back his head and screams in agony.
More often, he doesn’t bother with magic though. He uses his bare hands to bang Mordred’s head off every wall in the place, to wrap his fingers tight around his neck and squeeze, to knock him to the floor and kick him until his ribs splinter and crack.
He’s died more than once that way. Twice he’s bled out, lying where Merlin left him, feeling his life trickle out and stain the floor beneath him. Once he asphyxiates, Merlin’s belt pulled taut around his neck, his last conscious sight being cold blue eyes that watch intently as he gasps and twitches. The worst time is when Merlin simply ties him to a chair and leaves him, in a small wooden shack in the middle of nowhere. He’s so maddened by thirst on the second day that he forgets his vow to never try and escape, and he screams himself hoarse for help. But no-one comes and he dies two days later, choking on dry air.
It doesn’t always end like that. Sometimes when Merlin’s wrung his orgasm from him, he stills, calms. Lies down beside Mordred on the bed or the ground or wherever it is they find themselves. Twists his long fingers through Mordred’s hair and enfolds him in his arms.
Mordred has long since stopped believing that these tender moments signify forgiveness. But he aches for them all the same; clings to Merlin’s body when he is allowed, leans in to breathe his air, to inhale his scent.
Merlin still smells like the forests of Camelot, after all this time.
Merlin says Arthur’s name in his sleep, on the rare occasions that he stays the night. Mordred listens with a kind of desperate longing. He wants Merlin to sigh his own name like that. He wants Merlin to love him like he loves the memory of a dead man.
Above all, he wants to know when it will be enough. When his atonement will be complete.
Merlin says it will never be enough, but Mordred can’t bring himself to believe that. If he did, he’d give up now. He holds on to the image in his mind’s eye of a smiling man, who never turned his back on the hopeless, or shut his heart to pity. He remembers Merlin as he was, in flashes, remembers him as a healer, as a peacemaker, as a friend to all.
A small part of him whispers that Merlin was never his friend. That Merlin always distrusted him, watched him with wary eyes, waited for him to go wrong. That Merlin believed him to be a deadly threat to Arthur right up until the day he became one.
If you had trusted me, he wants to say. If you’d have reached out to me then, if I’d had someone to turn to… things might have been different.
He never says this of course but Merlin reads it in his thoughts anyway, and laughs mockingly, his hand fisted in Mordred’s hair.
“It could never have been different,” he hisses. “You were always going to do what you did. You were always irredeemable.”
Mordred cries then, even though he knows how Merlin hates it, because there must be some way to recover what was lost. There must be some way he can be saved.
“Never,” Merlin whispers, carving the word into Mordred’s skin with magic, raw and unmistakable.
After he leaves, Mordred sits on the floor and thinks the same thing that he does every time, that there will only be an end to this madness the day Arthur rises again.
He prays for that day to come soon, and he hopes it never does.