Notes: written for my friend Mikayla's birthday! Credit for the premise goes to my other friend, Jaida.

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Dean Winchester is six months old, and his babysitter is burning on the ceiling. He screams and screams and screams and then his mother is there, scooping him up and holding him close and she's crying and his father is yelling and there are flashing lights and night air and strange people talking over him and nobody notices the smudge of red in the corner of his mouth.

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Dean is four years old, and his mother is handing him a tiny pink person.

"Careful; hold his head. That's right. Dean, this is Sammy. He's your little brother."

The tiny pink person is warm and heavier than Dean expected. He doesn't have very much hair and smells kind of funny. He blinks up at Dean with large hazel eyes, and Dean thinks they're the prettiest things he's ever seen.

"My little brother," Dean repeats reverently, staring down at him. "Only mine?" he asks, looking to his mother for confirmation. This is important.

"Only yours," Mom agrees with a smile.

"Hear that, Sammy?" Dean says, all his attention back on the bundle in his arms. "You're my little brother. That means I'm gonna watch out for you. Forever and ever."

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Dean is nine years and three hundred and sixty-four days old, and he doesn't remember much from before Sammy was born. Or rather, he does, but only in the form of 'always.' Mom has always cut the crusts off his sandwiches. Dad has always read to him on Sunday evenings. There's always been a shotgun in the closet next to the door, which Mom says he can learn to use when he's ten.

And he and Sammy have always shared a room. They used to have a bigger house, Mom says, but there was a fire (and then she and Dad exchange dark looks and Dean doesn't ask any more questions, which is something else that's always been). Sometimes Dean's annoyed about it, because all his friends have their own room and Sam is little and weird and freaks out if any of Dean's stuff is on his side even a little bit, but mostly it's okay. Mostly it's more than okay, even (especially) when Sam wakes up in the middle of the night and crawls into Dean's bed and falls back asleep with his head tucked against his chest.

Tonight Dean welcomes his brother's arrival, pulling Sammy close until he can feel his heartbeat. It's still fast from whatever nightmare woke him, a fearful echo of Dean's, which pounds in excitement at the thought of what tomorrow brings, but Sam takes hold of Dean's shirt and Dean runs a hand through his brother's hair and slowly, wordlessly, they calm each other. Sam sinks into a peaceful slumber just minutes before Dean does, the glowing display of the clock reading 10:24.

One hour and thirty-six minutes later, he jerks awake to the sound of Sammy screaming. He might not remember the fire but there's something there, enough that he's dragging Sammy from the bed and out the door at the first glimpse of flickering orange light before he even registers the heat or the smell of smoke.

It's only once they're both in the hallway that Dean looks back.

His heart stops.

Mom.

But then Dad is there, panicked, yelling,

"Dean! Take your brother outside as fast as you can! Go!"

Dean obeys. The January air is frigid, cold biting at his ears as smoke burns his eyes, and there are sirens in the distance and Dad is coming out of the flames but Mom isn't with him, and she was – there was blood – she was on the ceiling –

Sammy is sobbing.

Dean sinks down onto the curb and pulls his little brother close, rocking him gently like Mom does – like she – like Mom.

"It's okay, Sammy." His voice is shaking. He tries to make it stop. "It's going to be okay. I've got you."

.

Dean is fourteen years old, and he knows how to use a shotgun. He also knows how to use a nine millimeter, and a revolver, and a bowie knife, and a dagger, and a bow and arrow, and a lot of other things.

Sammy knows how to use most of those things, too. Solemn, silent Sammy who barely says a word to anyone except Dean. Scared, sad Sammy who can't sleep on his own and has breakdowns if he's away from Dean for more than a day. Sharp, strange Sammy who recites Latin exorcisms obsessively under his breath.

He's not cut out for this life, Dean thinks, watching his little brother breeze through his math homework, lips moving silently. Dean adjusted to it quickly (easily), vengeance for his mother and duty to his father and fear for his brother giving him all the motivation he needed to learn fast and not complain. Sam learned, too, and he doesn't complain, mostly because he doesn't really talk, but it's not the same. (Sam doesn't enjoy it.)

Small, soft Sammy. He wouldn't last a day on his own.

Good thing he has Dean to protect him.

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Dean is twenty-two years old, and he can move things with his mind.

It's completely unexpected, the first time. A hunt has gone wrong and Dean is pinned and Dad is nowhere in sight and Sammy is hurt and unarmed gasping in fear and pain and that thing is advancing on him and that is not okay and it needs to stop right now.

And it does.

Actually, it doesn't just stop; it goes flying backwards as if it's been hit by a truck.

It's kind of really incredibly awesome, even though it's freaky as hell.

The thing hits the ground and doesn't get up again. Sammy (no longer small or silent but still soft where it counts) is staring at Dean with wide, wide eyes. Dean stares back, heart racing.

What. The. Hell.

Dean can hear Dad's footsteps approaching, and he makes a split-second decision.

"Good thing you got to the shotgun in time, hey, Sammy?"

Sam hesitates, just for a moment, and then nods shakily.

"Yeah. Good thing."

Dean can taste his own blood on his teeth. He grins.

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Dean is twenty-two and a half years old, and his brother will not shut up.

"It's dangerous, Dean. Can't you see what's happening? It's changing you."

"Dude, relax. I've got a handle on it."

"No, you don't. These powers – they're from the demon, Dean."

"I know that," Dean snaps. He's not an idiot. "That's why I've gotta work with them. Take ownership, y'know? Turn its own weapons against it."

"You can't. It's five steps ahead of us, man. It's been manipulating you from day one. It knew killing Mom would send Dad off the rails; knew he would drag us with him –"

"Sam." Dean cuts him off, and he falls silent, trembling. He's tense as a bowstring, trying to look angry, but Dean has always known him better than he knows himself. The kid's just scared, that's all. He doesn't understand. Dean softens his tone. "Sammy. It's just for a little while. We'll get the yellow-eyed son of bitch, and then it will all be over. I promise."

Sam bites his lip, uncertain, but Dean can see him folding. Sam can't fight Dean any more than Dean can refuse Sam, not since those months, years of clinging to each other in the aftermath of Mom's death.

"Hey." Dean forces Sam to meet his eyes with a firm hand on the back of his neck. "Trust me?"

Sam nods. There's still fear in those shining hazel eyes, but not a moment of hesitation. Dean smiles.

"That's my boy."

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Dean is twenty-three years old, and his father is telling him to kill him.

"You shoot me, son! That's an order!"

Dean hesitates. His gaze darts to the crumpled, bloody figure on the other side of the room. His father screams in pain. His mother burns behind his eyes. His brother doesn't move.

He pulls the trigger.

Later, in the hospital, he has to tell Sam. Sam doesn't cry or shout or even flinch, just stays silent for so long that Dean thinks maybe he's so hazy from painkillers that he doesn't understand. When he finally speaks, there's no fury, no accusation. His eyes are a little unfocused, and his voice seems to be coming from far away.

"I have dreams, sometimes. Where everything's the same, but different. I think . . . I think maybe it wasn't supposed to be this way."

"No such thing as 'supposed to be,' Sammy," Dean says, but Sam's eyes are already sliding shut. For once, he doesn't twitch or cry in his sleep, drugs and exhaustion granting him a peaceful slumber. Dean still holds his hand until he wakes.

There's no way he's letting go of the only thing he has left.

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Dean is twenty-four years old, and he wakes to the sound of movement. Silently, he pushes himself up, waiting until Sam is halfway across the room before speaking.

"Going somewhere, Sammy?"

His brother freezes.

"Dean." Sam turns. His eyes are shining with tears in the dim yellow light which filters through the motel room window, but his jaw is set. "I'm sorry. I . . . I was going to call you once I got there."

"Got where?" Dean demands, getting to his feet. Sam has his duffle packed and swung over his shoulder, ready to walk out along with every hint that he was ever there.

"Oklahoma," says Sam. There's no defiance in his tired tone, but no question, either. "The University of Oklahoma, actually. Not exactly Ivy League, but I got into their honors college, and they're giving me a full ride . . ."

"University," Dean repeats flatly. Sam drops his gaze. "And, what, you were just going to take off? Ditch me to become some college kid?"

"What else am I supposed to do, Dean?" Sam snaps, his head jerking up again. There's the anger, the defiance. "The demon's dead, Dad's dead, and you – you said it would be over, but it's not. We're still hunting, you're still using your powers, you've got freaking demon henchmen –"

"They're contacts," Dean protests. "Double-agents."

"They're your subjects, Dean. They worship you."

Dean shrugs. So a bunch of demons think he's the Second Coming, or whatever the demon equivalent is. If they want to fall at his feet and obey his every command, he isn't going to argue.

"You don't even –" Sam shakes his head, throat working, eyes cutting away. When he continues again his voice has lost its heat, fire choked in tears. "I can't. I can't stop you and I can't fix things and I can't – I just can't. So I'm leaving, before . . ." He trails off, unwilling to finish the sentence, and begins to turn away.

"No you're not," Dean states. Sam stops, looking over his shoulder. He looks like his heart is breaking, and his words don't come out as strong as he probably intended them to be.

"I'm not asking your permission. Goodbye, Dean."

He opens the door. Dean flicks his fingers. The handle jerks out of Sam's hand, and the shudder of the door slamming shut reverberates through the thin walls.

"I said no."

Sam spins to face him. He looks terrified, and Dean feels a pang of guilt. He shoves it down. This is for Sam's own good. He might be taller now, but at heart he's still just a traumatized kid clinging to his brother. He always will be. His belief that he can survive on his own is a delusion, a temporary one, and Dean's not going to let him chase it only to crash and burn when it shatters.

Dean steps forward. Sam's duffle hits the ground, and suddenly the Colt is in his hand. Dean has to hand it to the kid, he's fast.

"Dean." Sam's voice is shaking, now. So are his hands, so badly that he's forced to aim at Dean's chest rather than his head for fear of missing. It's kind of cute, really, that he even thinks that will be an issue. "Please. Don't – don't make me –"

"Don't make you what, Sammy?" Dean asks, taking another step forward. "Shoot me?" Another step. Sam's back hits the door. His hands are wavering so badly that the gun might go off by accident, might even ricochet and hit Sam. Dean frowns at the thought and moves to take it away. Sam struggles to steady it.

"Don't – Dean – please—"

Dean pauses and holds out his arms, leaving himself wide open.

"So shoot me."

Sam stares at him for an endless moment, eyes shimmering, face pale.

The gun clatters to the ground. Sam follows it a moment later, sinking down and covering his face with his hands. His shoulders hitch as he begins to sob.

"Sammy," Dean sighs, sinking down as well, joining his brother against the door. Sam flinches when he reaches to put an arm around his shoulders, but Dean ignores it and pulls him close. "Hey, hey. Easy. You know I'd never hurt you, Sammy."

Sam shudders, but pulls his hands away and buries his face in Dean's shoulder instead. There will be time for anger and recriminations later; Dean knows that there will be plenty of that, from both of them. But right now, with Sammy huddled against him, choking on broken sobs, there's only one thing that matters. (Only one thing that's true.)

Cheek resting on Sam's hair, hand rubbing his shoulder comfortingly, Dean declares it like a law of the universe, undeniable, irrefutable.

"You're my little brother. That means I'm gonna watch out for you."

Forever and ever.

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Dean Winchester is twenty-five, and he sits upon the throne which he has been told is his, which he has fought to obtain and will fight to keep. He doesn't know or care if it's right. If anyone burns, it will be with his say-so.

And nothing will hurt his little brother.