Author's Note: This is a series I've had in mind for quite a while now - portraying certain pivotal moments in characters' lives where things could have taken a completely different path. I'm focusing on the Blacks, both because they're my favorite characters and because they're so tragic, and there are so many opportunities where things could have been different.

As always, none of the characters are mine.

Reality:

He blocks out his brother's words, though something in him desperately wants to hear them. They are poison, he tells himself fiercely; they are the words of a traitor. It is his own self-defense ritual in response to the fact made painfully clear to him today: that Sirius's friends are far more important to him than his family.

"No," he says stiffly, letting no emotion snake itself into his voice, thereby giving him away. He has a fleeting thought of a statue, a cold marble body without warmth or life, before he pushes it away.

He catches disappointment flash over Sirius's face, and darkly, he's glad that Sirius is hurting, even a little bit. It's nothing compared to the pain Regulus will feel as soon as his older brother walks out the door, but it does mean that there is some justice in the world, something he has been doubting for a long time.

"Are you sure?" Sirius asks, making his voice devoid of emotion as well. It's uncanny how much they mirror each other, sometimes, Regulus notes. Uncanny and completely tragic. There is no genuine feel to Sirius's voice now. He is going through the perfunctory motions so that he will not be cast as the villain who abandoned his brother.

Regulus nods, unable to meet Sirius's eyes. The truth is that he isn't sure, but he has to be, which means allowing no room for doubt or other possibilities. He turns and walks away, not wanting to hear the slam of the door as Sirius leaves the house forever.

-

Five years later:

With each drink of the potion he takes, Regulus relives his most shameful and excruciatingly painful memories. He relives the first time he ever committed murder, the first time he administered the Cruciatus Curse. And then, perhaps the greatest horror, he remembers that look of pain on Sirius's face, then all the meetings at Hogwarts afterward, marked only by blank stares, as if they never were brothers at all.

It is a million times worse than physical pain. His mind is screaming, and he cannot concentrate on anything else but the images in his mind and the sounds. He manages, though he doesn't know how, to croak for water, and Kreacher rushes to get some from the lake and put it into a goblet.

And then the Inferi come, pale and emotionless, with only one purpose to carry out. With his last burst of strength, Regulus shouts to Kreacher to leave, to return home, tossing him the locket. It is not heroic; it is simply pragmatic. Then, still with the images and the sounds making chaos out of his mind, he faces his attackers.

This is an end Sirius would be proud of, he thinks, as Sirius's scorn flashes through his mind.

He feels fingers wrap themselves around his arms, and he's too weak to fight. He's screaming, though they seem distant to his ears. In a few moments, he realizes that he's underwater, and the pain in his mind eases.

This is his end, then, he thinks, the last chapter of his story. He glances at the Inferi, pushing him further and further down, then looks through them, back towards the surface. He sees the world that he's left behind, full of regrets and pain and sadness.

He closes his eyes then, and doesn't fight.

-

But maybe:

Regulus hesitates. He hears his brother's words as if they are temptation itself and he is Eve, and he knows that he should resist; they urge him to throw everything that he has away and cannonball into the unknown. He is not a risk-taker; he is sensible. He likes solid subjects like Transfiguration where there is a set result, not classes that involve ambiguity.

There is no explanation for why he finds the possibility so exciting, so wonderful.

For the first time, he closes his eyes and leaps. He pushes all of the negative thoughts out of his mind, and nods. Surprisingly, he is not ashamed as tears well up in his eyes – whether they are from pride in himself or grief at what he is leaving behind, he isn't sure, but for once he is not concerned with how others will perceive him. He begins to go upstairs to pack his things when Sirius stops him.
"We don't need anything, Reg!" His voice is so loud and exultant that Regulus thinks it must be a kind of miracle if his parents sleep through it, then realizes that the risk is partially why Sirius is doing it. A split-second later, he remembers that his parents' reactions will no longer faze either of them.

He lets out a whoop of his own, just as loud and vibrant as his brother's.

Sirius grins, and it is like the sun – warm and bright and lovely. He could bask in this moment forever.

-

Five years later:

Regulus is fighting for his life.

His wand makes slashes and produces light, but none of them seem to hit his opponent, and he, Regulus, now sports deep, bloody gashes on his body. It's an effort to stand, much less cast curses, and he knows that a few more minutes will pass, and he will be gone.

It's not a bad place to die, he thinks, as he manages to just avoid one of Dolohov's curses. Sirius would be proud; Sirius would think it to be a good death. It's a comforting thought, but it also brings out the last reserve of strength that he has.

He moves with new energy that doesn't even seem to come from him, as he duels for what he is sure will be the last time. He doesn't let himself consider what his death will mean for his brother, for Andromeda, for his new friends in the Order, maybe even for his long-estranged parents and cousins. Instead, he thinks of the glory he will receive, and that is enough.

His newfound energy leaves him gradually, leaving him weaker than he has ever been in his life. Just when Dolohov raises his wand to deliver the curse that will end his life, a jet of red light hits Regulus's attacker.

Dark hair and a face that looks strikingly similar to his own swims into his sight.

"Sirius?"

"Come on, Regulus, let's get you fixed up."

Dimly, Regulus sees that the battle is over, at least for now, and that he is alive, against all odds. He lets himself lean on his brother for support as they Disapparate to St. Mungo's.

"Sirius?"

"Yeah?"

"Thank you."