**August 31, 1971**
The air in the dining room of Number 12, Grimmauld Place, hung heavy, as if the house itself was holding its breath.
Tomorrow, Sirius would board the train to Hogwarts. Walburga had spent the entire week in a state of frantic, aggressive preparation.
"Remember," she said, slicing her lamb chop with unnecessary force. It was the tenth time she had said it that hour. "You represent the House of Black. You are not just a boy; you are a legacy. Once you board that train, find the Slytherin compartment. Do not associate with the riffraff. Do not go with those—"
"I won't go to Slytherin."
Sirius's voice was soft, but it stopped the dinner conversation dead.
Walburga's fork froze halfway to her mouth. The silver glinted in the candlelight. "What did you say?"
"I said I am not going to Slytherin," Sirius repeated. He kept his eyes fixed on his plate, refusing to look at her. "I'm going to Gryffindor."
A hush fell over the table. It was absolute.
Even the portraits on the walls ceased their murmuring. Phineas Nigellus stared wide-eyed from his frame, mouth agape like a fish on dry land.
Orion slowly set down his wine glass. The red liquid settled instantly. "The Sorting Hat considers the student's preference, Sirius. But it also weighs lineage, traits, and destiny. The Black family has been in Slytherin for five hundred years."
"Then I'll be the one to break the streak," Sirius said stubbornly, his grip tightening on his knife. "I don't want to spend seven years with a bunch of upright ass holes snakes."
"Snakes?" Walburga's voice trembled, rising in pitch. "That is your heritage! That is your glory!"
"It's a cage!" Sirius shouted, finally looking up. His face was flushed. "I don't need Black glory! I just need to be myself!"
He turned his head to look at Regulus.
His ten-year-old brother was sitting calmly, cutting a piece of steak into a perfect square and placing it in his mouth. The contrast between Sirius's fire and Regulus's ice was stark.
"And you?" Sirius sneered. "You'll go to Slytherin, won't you? You'll be the perfect heir. Study hard, bow low, and wait for the day you can inherit this rotting house."
Regulus chewed, swallowed, and dabbed his mouth with a napkin.
"I will go where I fit," Regulus said simply.
"Fit?" Sirius let out a harsh, barking laugh. "There is only one place fit for you, little brother. The dungeons. With the other lunatics who think blood makes them gods. Have a good time down there."
He threw his napkin onto the table, pushed his chair back with a screech of wood on wood, and stormed out of the room.
Walburga slumped back in her chair, her face draining of color. Orion remained expressionless, staring at the tablecloth, but the candles in the room flared violently, responding to the surge of his suppressed magic.
Regulus picked up his fork and continued to eat.
He knew what was coming. In the original timeline, Sirius went to Gryffindor. He became the outcast, the traitor, the first crack in the House of Black.
He also knew that starting tomorrow, everything in this house would change.
◈ ◈ ◈
**September 1, 1971**
The owl arrived at dusk.
Walburga snatched the envelope from the bird's beak. Her hands shook uncontrollably as she tore the parchment open.
She scanned the single line of ink.
Her face went from pale to ash grey. Her lips quivered, trying to form a word that wouldn't come. Then, her eyes rolled back, and she collapsed backward.
Orion caught her with one arm, snatching the falling letter with the other.
He read the verdict.
*Sirius Black has been sorted into Gryffindor.*
That night, the atmosphere at Number 12, Grimmauld Place, was not one of celebration. It was one of mourning. The silence was thick enough to choke on.
But Regulus knew this was just the beginning.
From the next morning onward, the spotlight shifted. Walburga turned her terrifying, suffocating attention entirely to him.
"You must be ten times better than him," she hissed over breakfast, her eyes feverish. "No, a hundred times better! You must prove that the blood is not corrupted. You must prove that the true heir is still here."
Regulus nodded. "Yes, Mother."
It was exactly what he had calculated. The price was Sirius's exile, but the reward was freedom within the walls.
He gained new privileges: unlimited access to the library, permission to borrow from the Family Heritage section, and even the right to peruse low-risk experimental journals under Orion's supervision.
With Sirius gone, the mansion was quieter. Regulus settled into a disciplined rhythm: four hours in the library, two hours in the attic, and the rest enduring his mother's lectures and his father's inspections.
His "cyclical training"—pushing magic through his body to expand his capacity—was yielding terrifying results.
His magical core was expanding, slowly but steadily. It was like digging a well; each day he removed a little more earth, and each day the water rose deeper.
Every night before sleep, Regulus sat cross-legged on his bed.
*Breathe in.* Pull the magic from the core.
*Breathe out.* Push it through the limbs, the bones, the blood.
It was no longer an exercise of imagination. The magic had developed a memory. It flowed naturally along the pathways he had carved, like a river settling into its bed.
His control was becoming surgical.
He could make a floating feather trace perfect, geometric circles in the air with a margin of error less than a millimeter. He could touch the surface of a glass of water and create a single, standing ripple that refused to dissipate for minutes.
This was the synchronization of will and power.
And his recovery was faster. Where he used to need sleep after heavy casting, he could now simply cycle the magic to refresh his stamina. Just as an athlete stretches to clear lactic acid, Regulus used the flow of magic to clear the fatigue from his nerves.
◈ ◈ ◈
**Fall 1971 – Spring 1972**
With Sirius gone, the cousins visited more often. They came to inspect the remaining heir.
**Bellatrix** came first. At twenty, she was a terrifying force of nature. She was a fully fledged follower of the Dark Lord, her eyes burning with a fanaticism that made the air cold.
"The world is sick, Regulus," she told him one afternoon in the garden, swinging her wand like a blade. "Filthy Muggle blood pollutes our magic. Half-breeds dilute our power. The Ministry is run by cowards who are afraid to act."
She turned to him, her smile sharp as broken glass. "We need a cleansing."
"A cleansing?" Regulus asked, watching her behead a flower with a hex.
"Purification," Bella whispered. "The Dark Lord will guide us. He has the power, the vision, and the determination. When he rises, pure-bloods will rule. Not as equals. As masters."
"And who will be left to rule?" Regulus asked quietly.
He looked at his cousin and saw her future clearly: madness, Azkaban, death. He couldn't stop it. He didn't intend to.
"Everyone!" Bella laughed, a sound like tearing silk. "Muggles, mudbloods, traitors. They will find their place. Beneath us."
"Narcissa" was different. At sixteen, she was a prefect at Hogwarts, the ice queen of Slytherin. She didn't preach ideology; she taught survival.
"Bella has her path," Narcissa told him privately over tea. "But you must find yours. Slytherin isn't just about fanaticism, Regulus. It is about wisdom."
"Wisdom?"
"Weighing the cost," Narcissa said, poking a piece of cake with her silver fork. "Knowing when to advance and when to retreat. Knowing who is useful and who is dangerous. Knowing what to say and what to keep hidden."
She leaned in, her voice lowering. "Always have three excuses ready. If you are caught out of bed, have one for the professor ('I was lost'), one for the prefect ('I lost my pet'), and one for your friends (the truth, but only if they are useful)."
"Never let anyone know you completely," she advised, her blue eyes piercing his. "Not even your best friend. Keep at least one secret. Secrets are armor. In Slytherin, value is currency. Find out what you are worth—knowledge, resources, protection—and make people pay for it."
Regulus listened. Narcissa was cold, but she was right.
**Andromeda** visited last. Regulus cared for her the most. She was the only one who looked at him and saw a boy, not an heir.
At seventeen, she was a pariah in the making. She ignored the pure-blood cliques at school, spending her time with half-bloods and Ravenclaws. Walburga had all but banned her from the house.
It was a rainy day in March 1972 when she found Regulus in his room.
"I'm leaving," she said bluntly.
"Where?"
"Away from Britain," Andromeda said, watching the rain streak the windowpane. "I'm going to marry Ted. He's a Muggle-born. You know what that means."
Regulus nodded. It meant being burned off the tapestry. It meant being dead to the family.
"Are you scared?" he asked.
"Terrified," Andromeda admitted softly. "I'm afraid of losing my family. I'm afraid of the future. But I'm more afraid of staying here and slowly becoming someone I don't recognize."
She turned to face him, placing a hand on his shoulder.
"I know you are different from Sirius. You are smart. You are rational. You know how to compromise."
Her grip tightened slightly. "But don't let compromise turn into surrender, Regulus. Don't let this house eat you alive. You have a heart. Remember it."
Regulus was silent for a long time. "Thank you."
"Take care," Andromeda said. She walked to the door, then paused. "If... if one day you need help. Real help. Find me. I'll be in France."
She left the room, leaving the door slightly ajar.
Another Black was gone.
Regulus looked out at the rain washing over London. The house was emptying. The cracks were widening.
*Just me now,* he thought. *Just me and the ghosts.*