Looking as efficient as ever, Professor McGonagall scanned the scroll in her hands, her voice commanding attention as she called out, "Black, Regulus!"

Regulus's heart quickened, each beat a drum of nervous energy. As he walked toward the stool, he could feel eyes following his every step. He reached for the Hat with slightly trembling hands, lifting it with a sense of both anticipation and dread. He knew where he wanted to end up, where he belonged—and the fact that Sirius had ended up elsewhere still gnawed at him, a betrayal of everything they had been taught.

He placed the Sorting Hat on his head and stared into its darkness, his mind whirling with thoughts he tried to keep hidden. For a moment, he thought he heard a small, amused chuckle echo in his ears, but before he could ponder its source, the Hat vibrated ever so slightly. Then its booming voice filled the Great Hall: "Slytherin!"

A wave of relief washed over him as he made his way to the Slytherin table, a smile creeping onto his face despite his earlier nerves. The sense of accomplishment was undeniable. He had upheld Black family traditions. He had proven his talents belonged in the house of Salazar Slytherin, the house of cunning and ambition.

But even as he sat down, lost in the moment of triumph, he instinctively searched the far end of the hall. His eyes quickly found the Gryffindor table, where his brother Sirius sat, half-grinning, raising his goblet in a silent toast before downing his pumpkin juice in one swift gulp. The gesture was casual, almost indifferent, but it held layers of unspoken meaning. For a fleeting moment, Regulus felt a pang of guilt, sharp and unwelcome. His sorting into Slytherin would surely drive an even deeper wedge between them.

Why did he have to be so stubborn? Regulus thought to himself, stifling a groan.

But by the time the feast began, and the plates piled high with food, his mind was soon filled with the satisfaction of knowing how pleased his family would be. For once, Regulus felt like the rightful heir to the Black legacy, surrounded by the comforting green glow of his new house. Sirius, with his reckless defiance, faded to the back of his mind. Almost.

The next morning, however, it all came flooding back. At breakfast, Regulus spotted Sirius deep in animated conversation with James Potter and two other Gryffindor boys. Sirius and James were the center of attention, their laughter ringing through the hall, carefree and loud. A flicker of irritation burned in Regulus's chest. Seeing his brother laughing so easily, surrounded by friends, made him feel something he couldn't quite name. A Black never shows emotion in public, he reminded himself firmly, though the memories kept coming back unbidden, threatening to crack his composure.

He remembered Sirius sneaking into the kitchen at Grimmauld Place to steal jam tarts for him when Regulus woke up hungry in the middle of the night. Sirius, with his infectious grin, teaching him how to mount a broom and zooming around the yard, laughing as he threw objects for Regulus to catch. Sirius always owning up to the trouble they got into, like the time they broke the vase in the living room. Those were the moments Regulus had cherished, even though they felt like they belonged to another lifetime.

But then came the day Sirius left for Hogwarts, and everything changed. Regulus could still hear his mother's shrill fury when the letter arrived, confirming that Sirius had been sorted into Gryffindor. The shame it brought to the family was palpable, and Walburga Black had raged for days, refusing to speak of her eldest son unless it was to berate him. When Sirius wrote to say he wouldn't be coming home for Christmas that year, their parents were visibly relieved, and Regulus quietly learned not to ask too many questions.

When summer finally came, Sirius returned, and the hostility that followed was unbearable. His father's cold silence, his mother's outright refusal to acknowledge Sirius's presence, the way their parents acted as though Sirius were no longer part of the family. Regulus had watched it all unfold, caught in the middle, too young and too afraid to intervene. His parents wouldn't even allow him near Sirius, afraid that their "wayward" eldest son would taint Regulus with dangerous ideas.

Regulus had always admired his brother's rebellious spirit, but he couldn't say it aloud. His parents would never tolerate such talk, and he wasn't foolish enough to risk their wrath. So he stayed silent, adopting the Pure-blood values that had been drilled into him from birth. He convinced himself that Slytherin was where he was meant to be, where he could make a name for himself, even if it meant watching his family fall apart.

Sirius handled the rejection with his usual coolness, though he never stopped rebelling. After all, rebellion seemed to run in his veins. The first thing Sirius did after returning home was spread a Gryffindor banner across his bed. His father's reaction was swift and unforgiving—he threatened to lock Sirius in his room if anything remotely Gryffindor-related surfaced again. But Sirius was unbothered.

The next day, when their mother went to check if the offending banner had been removed, she froze in the doorway, her face contorting with fury. Sirius had not left the banner lying around. No, he had affixed it to the wall above his bed with a Permanent Sticking Charm. Walburga's scream of outrage echoed through the house, and punishments followed, but the banner stayed.

That summer dragged on, filled with tense silences and explosive arguments. Sirius continued to antagonize their parents, and Regulus found himself increasingly caught in the crossfire. His brother's defiance was a constant source of irritation for their parents, and Regulus soon realized that life would be much simpler if Sirius just stayed away. By the time the summer ended and Sirius left for his second year at Hogwarts, Regulus was relieved.

Each time Sirius returned, things grew worse. His pranks became more elaborate, and their parents' punishments more severe. Regulus could no longer understand his brother. Why provoke them? Why make things harder than they already were? But deep down, he knew the answer. Sirius had always been reckless, always drawn to danger, never afraid of the consequences.

One night, Regulus woke to the sound of screaming. His heart raced as he crept out of bed, his wand clutched tightly in his hand. He knew what was happening. He had heard his parents talk about it before—the Cruciatus Curse. He had never imagined it would come to this, but there was no mistaking the high-pitched screams that echoed through the house. Sirius was in trouble.

He moved quickly but quietly, his mind racing. What could he do? He was barely thirteen, just a boy who had finished his second year at Hogwarts. But he couldn't stand by and watch his brother be tortured. He had to do something, anything.

As he reached the door to the sitting room, he caught a glimpse through the crack. His brother lay on the floor, bloodied and broken, while their father stood over him, wand raised. Panic surged through Regulus. His mind went blank, and before he knew it, he was shouting the first spell that came to him.

"Wingardium Leviosa!"

Sirius's body lifted off the ground, and with a force Regulus didn't know he possessed, he flung his brother out of the nearest window, glass shattering as Sirius's body hurtled through the air.

He hoped—prayed—that Sirius had the strength to Apparate away, that he would survive this. His father turned to face him, eyes cold and unseeing, as if Regulus wasn't even there. With a dismissive snarl, he muttered, "Good riddance," and walked away.

The next morning, the Black family had erased Sirius from their lives for good. His name was blasted from the family tree, and the incident was never spoken of again.

But Regulus never forgot. He never forgave.

When news of his father's death reached him a few years later, Regulus remained strangely calm. There were no tears, no outbursts, only a quiet, eerie acceptance. While his mother mourned, inconsolable over the loss of her husband, Regulus found his thoughts wandering in an unexpected direction—toward Sirius.

In the silence of Grimmauld Place, with only Kreacher moving about like a shadow, Regulus sat in his father's old study. It felt oppressive, full of books on pure-blood supremacy, dark magic, and the twisted history of their lineage. The Black family motto, Toujours Pur, adorned the walls, a constant reminder of the expectations he had lived under. But now, as the new head of the Black family, those expectations were his to redefine.

His decision came swiftly, as if it had been waiting, buried in his mind for years. The first thing he did, as the new master of the house, was reinstate his brother as the eldest of the Blacks—albeit in secret. He knew his mother would never agree, would never accept this silent rebellion, but it didn't matter. Regulus wasn't doing it for her. He wasn't even sure if he was doing it for Sirius. Maybe it was for himself, a quiet rebellion against the parents who had robbed him of his older sibling.

Being at Hogwarts had only deepened the rift between the brothers. The Sorting had divided them physically, emotionally, and symbolically. To their parents, Regulus's Sorting had been a victory, a restoration of Black family honor after the embarrassment Sirius had caused. But for Regulus, it was the beginning of an internal struggle he could never quite resolve.

Playing Quidditch against Gryffindor only worsened things, not when he was pitted against James Potter, both Seekers on their teams. Victories on the Quidditch pitch always came with a price, a reminder of what could never be repaired between them.

In those moments, Regulus couldn't help but feel a pang of regret. Had they destroyed more of their relationship by being sorted into different Houses? Could things have been different if Sirius had followed family tradition, if they had been on the same side? He shook the thoughts away, knowing that Sirius would never have conformed to the Black family's ideals. His brother was too wild, too free, too Sirius to ever settle into the mold that had been carved for him.

It was maddening, how easily Sirius seemed to have moved on from the ties that bound them. Regulus, on the other hand, had never been able to shed his sense of duty, the weight of his family name pressing down on him.

But no matter how far apart they drifted, Regulus could never quite shake the feeling that he and Sirius were bound by something more powerful than bloodlines or family traditions. It was as if an invisible thread connected them, one that neither of them could sever, no matter how hard they tried.

Perhaps, in the end, it was Sirius's influence, buried deep under layers of resentment and rivalry, that pushed Regulus to make the ultimate sacrifice.

A sacrifice that Sirius, perhaps, would have understood better than anyone.