Written for the March Fanfiction Tournament — pre-Hogwarts.

Also for Amber's Super Insane Prompt Challenge — number 3, sweet.

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"Sirius?" His voice is soft, frail. He hates it. He intended for the the word to come out brave, strong — like Sirius. He isn't like Sirius. He's never been like Sirius.

"Hey, Reg."

Sirius is staring at his brand new, shiny trunk. His name, Sirius O. Black, gleams across the front in shiny gold letters. He looks entranced, knees curled up to his chest, arms wrapped around them. His back is to the wall as he stares at the trunk on the other side of the room.

After a long moment, he finally looks up to see Regulus standing in the doorway, frame compressed to be as small as possible, vibrating. Sirius pats the bed next to him.

Without hesitation, Regulus scrambles up and leans against the wall beside him. Sirius puts his arm around Regulus' shoulders.

"It's going to be fine, Reg. You'll be all right."

Regulus curls into his arm. "You aren't a Slytherin, Siri. We both know it. You aren't like the rest of us. And you're going to go off to Hogwarts and be sorted and you're going to find people who are like you, people who are brave and strong and good like you. And you're going to leave me."

"Listen to me, Reg. You are as brave, as strong, as good as you want to be. And I am not going to leave you. I'm always going to be right here." He taps the younger boy's chest. "You'll always be my little brother, all right? That's not going to change."

"You're leaving." His voice is almost nonexistent.

Sirius' arms tighten around Regulus' shoulders. "I have to go, Regulus. You know that."

"I know. I just wish… I wish I could make you stay."

And Sirius knows that if anything, anything could possibly make him stay, it is Regulus. Leaving Regulus here alone is the only thing that makes his leaving bitter-sweet.

It isn't enough to stop him, if it even could.

"It doesn't work that way."

"I know."

"And even if it did, Regulus… I can't… I can't stay here any longer. I can't. I'd explode."

Regulus giggles at the image, and Sirius smiles at him fondly. "Promise me something?"

Regulus nods without hesitation.

"Promise me… you won't give her a reason. Don't be me. Be you. Be good. Toe the line."

Regulus frowns at his brother. Sirius has spent as long as he could talk encouraging Regulus to be a rebel, to make mischief, to get away with what he can and make sure it's worth it if he can't. Now he's saying be good?

Sensing Regulus' confusion, Sirius sighs. "I'm not going to be here to protect you," he says, knowing that Regulus still won't understand, knowing that Regulus does not know the depths of what Sirius has done for him. Knowing that, if Sirius has any say in the matter, he never will. "Be smart." He taps Regulus' forehead lightly. "Use that brain I know you've got. Merlin knows I don't have it." He grins, and after a half-beat pause, Regulus smiles back at him, but it's weak, tremulous.

"Promise me something back?" he asks.

And Sirius nods without hesitation.

"Promise you won't forget me?"

The words tear through Sirius, sharp like knives. Regulus doesn't mean them to hurt, but they still do.

"I promise, Reg," he says softly, resting his chin on the younger boy's head. "I promise."

He doesn't know it yet, but it is a promise he will keep forever. He will not forget his little brother – but he will not be able to save him. either. Sirius will stand by and watch as Regulus slips further and further beyond his grasp, and it will tear him apart.

But he will never forget.