Title: Once
Fandom: Fullmetal Alchemist & Supernatural
Author: Night's Fang
Characters/Pairings: Ed/Al, Dean/Sam
Rating: PG-13
Summary: They've lived before, and they'll live again. History will keep repeating itself for them. They live for each other, and because of that they'll live forever.
Warnings: Set through FMA, and SPN so there are spoilers for both. Mentions of violence and incest.
Disclaimer: I don't own Fullmetal Alchemist or it's characters, it belongs to Hiromu Arakawa. Similarly Eric Kripke and CW own Supernatural and it's characters. (Though sometimes I wish Arakawa owned it.)
A/N: The idea was inspired by a prompt left on comment_fic.

Once they were.

They were Edward Elric, and Alphonse Elric in another world. Children, Alchemists, brothers. A dead mother. Absent father figure. Hair of gold, eyes of gold, like the golden sage himself. And like the golden sage, cursed blood. When they lost, they grieved. Then they dreamt, and then they defied. Arrogant and childish they broke the laws of the world to bring back the mother that never could be brought back. Like so many others before them, and so many others that would come, they thought they could mould the world to their whims and fancies. They thought they could bend the world to their knees.

They knocked on God's doors, and disturbed him from his exile. But here God was The World. The World was Truth, and Truth is not merciful. It was cruel and harsh and unforgiving. So Truth laughed through Edward's screams as the knowledge of the world poured itself into his tiny head. He smiled as he took Edward's limbs. He grinned as he took Alphonse's body. He laughed through Edward's sobbing and screams of Give him back; Return him back to me; He's my only little brother, as he sacrificed another limb for the younger's soul. He laughed and laughed and laughed, loudly, insanely; as Edward angry, and Alphonse's body soft and not quite soulless inside the Gate – like so many had before, and so many who would come – promised to get back what they had lost.

They became soldiers, Ed with metal limbs, and Al with a hollow metal body. They searched, Philosopher's stones, knowledge, salvation, atonement, answers. They gained, they lost; days, nights, time, friends, allies, family, childhood, innocence, themselves, love, each other. And through all that they fought; ideals, humans, monsters, they fought them all. They fought because they loved. They loved so strong, so much, that nothing could come between them.

Edward sacrificed his limbs for Alphonse's soul. Al reversed that so Edward could fight Father. And then Ed, arrogant smile on his face, stormed the Gate to take his brother back, and did it.

They brought the world to it's knees, moulded it to their whims and fancies, broke it's laws, conquered it. Truth lost.

They won.

o0o

Once they are.

They are Dean, and Sam Winchester in this world. Not quite children, Hunters, brothers. A dead mother, and a father who isn't really absent, but in a way is. Dark haired, and green eyed, like their father. Special bloodline, just like him. They're older, different, but their souls are still the same. They hunt for revenge, to save others, to find themselves. They're destined to be the carriers for the ones who will bend the world to it's knees. They're destined to break the world. They think they can fight the supernatural. They think they can fight destiny. They think they can fight Heaven and Hell.

It knocks on their doors this time. Keeps knocking, before they're born, keeps reminding them of what destiny says is in store for them. Lucifer tells Sam about loving too much. Michael tells Dean about family. They preach, and preach, and then they threaten, and then they do worse. The Winchesters should run, but they don't.

And History repeats itself a little differently, but essentially the same. They're still soldiers after all, Dean with his guilt, and Sam with demon blood flowing through his veins. They search for vengeance, for answers, for family, for hope, and they find it. They gain, and they lose; family, friends, lovers, childhood, everything, and a lot of times each other. And each time they lose each other it's worse then losing themselves. Give him back; Return him back to me; He's my only little brother, Dean screams mentally each time he loses Sam a bit more. When God hears those familiar words, he can't help but smile, because of the familiarity of them. The promises soon follow, arrogant and determined as before. This time He doesn't doubt them.

They still fight, because they love, and Heaven and Hell can fuck off please, because they aren't giving up. Michael and Lucifer can speak about destiny all they want, they can talk about love and brotherhood and family, but they don't care. They're going to go down fighting, if they have too, and not without each other. Never without each other. They're love for each other far outweighs the very existence of His creation. Far exceeds what Michael and Lucifer can comprehend.

Sam sacrifices himself to throw Lucifer back in, and take Michael with them. This time Dean doesn't do anything to bring him back, because this time Sam brings himself back.

They don't need someone else possessing them to bring a world to it's knees, they've done it once before. God shakes his head laughter bubbling through. His sons never stood a chance. Heaven and Hell lose.

They win.

o0o

Once they will be.

They will have different names, different bodies, but their souls will still be the same. They'll still be brothers, always be brothers, lovers, soldiers. History will repeat itself and they'll have a dead mother and an absent father. Destiny will call them, and they will answer. They will fight it because they still love, and never will stop. They'll break the world again, bend it to it's knees. Promises will be made, and God will watch through another façade and smile because He knows.

They'll stomp destiny into the ground. Maybe they'll kill Him. Maybe they'll kill Death. He doesn't know. All He knows is that, no matter what may come.

They'll always win.

Because they live for each other, they'll live forever.