Sirius stood on the left side of the training room, wand in hand, looking rattled.
He'd been called down here last summer too. Same routine: holiday just started, time to test his magical progress. Except that time, Orion had been his opponent.
It wasn't close. He'd been dismantled, left flat on his back staring at the ceiling, unable to get up for what felt like an age. His father had walked out without a word and gone back to work in the study next door.
This year was different. Orion wanted him to fight Regulus.
Sirius couldn't quite wrap his head around it. Him and Regulus? Dueling?
He knew what Regulus had done at Hogwarts. Beating fifth-years as a first-year. Taking down a seventh-year by spring term. Professors treating him like some kind of prodigy, giving him extra lessons at every turn.
But all of that was secondhand. Stories and rumors drifting through the corridors.
He'd never actually seen Regulus fight, except that one time on the Hogwarts Express at the start of term. And that had been over before it started. James's curse had been frozen mid-air and taken apart, and Sirius hadn't even followed how it happened.
Afterward, James had gone looking for Regulus to settle the score. He came back with a face cold enough to frost glass and refused to talk about it. Remus gave them the rundown later, but the way he described it, it sounded like ordinary first-year stuff. Nothing dramatic. And hearing about a fight was never the same as seeing one.
A thought flickered through his mind: Regulus could probably take me now, couldn't he?
The thought stung. He wasn't ready to accept it. He acknowledged Regulus's talent, always had. His little brother had been different from the start.
Wandless magic at three. Reversing Transfigurations at five. Before he'd even set foot in Hogwarts, he'd already surpassed most lower-year students.
Sirius also knew what that talent had cost. Hours upon hours buried in the family library. Training in the attic until deep into the night. If you wanted to find Regulus at school, the surest bet was to stake out the library.
But Sirius was a Black too. He might hate the name, might despise everything it stood for, but the fact remained: no Black was born without power.
He was a year and a half older. A full year ahead in school. And he was no slouch at Hogwarts either.
The Marauders. Everyone knew the Marauders.
Night raids, pranks, brawls with Slytherin. He'd never once backed down.
So where exactly was he lacking?
He wanted to find out. Wanted to measure the gap between them with his own hands. Wanted to see the thing Regulus was chasing so relentlessly, this force that drove his brother forward. What it actually looked like up close.
Sirius pulled himself back to the present and said one word: "Fine."
He looked at Regulus. But Regulus wasn't looking at him. Those grey eyes were fixed on Orion, and the question in them was unmistakable: You're serious?
Orion met his gaze and gave the faintest nod.
Regulus understood. His father's meaning was simple: Beat it into him.
Make Sirius understand what strength meant. Make him realize he needed to get stronger, even if the only way to light that fire was the oldest, most primitive motivator there was: getting hit hard enough to want to hit back.
Regulus thought this was necessary.
Sirius had talent. He would master the Animagus transformation, though that was for a friend's sake, so he could be there on full-moon nights with Remus the Werewolf.
But the Animagus transformation was advanced Transfiguration by any measure. It demanded extraordinary magical control, patience, willpower, and no small amount of luck. In the entire twentieth century, only seven Animagi had been registered with the British wizarding community. The fact that Sirius would pull it off proved his raw ability was anything but lacking.
The problem was drive.
Sirius had never felt a genuine desire to become powerful. Not for power's own sake.
He learned magic because it was fun. Because it made for better pranks. Because it let him go on adventures with his friends.
He was pursuing the Animagus transformation for friendship, not for strength itself.
That kind of motivation could push someone to master specific skills, but it would never fuel systematic, sustained growth.
Regulus was cut from different cloth. He'd mapped out his path long ago, and every step on it demanded power as a foundation, strength as a guarantee. He had to face the threat of Voldemort, protect the family, survive whatever conflicts lay ahead, and reach for the stars.
Every one of those goals required him to grow stronger. Always stronger.
He hoped he could ignite something in Sirius. Some spark of personal ambition toward magic. It didn't need to be grand.
Protecting friends. Having the strength to fight back when danger came. Not being a burden to the people who mattered. Any of those reasons would do.
But Sirius didn't have that yet. All he saw was friendship and adventure. He couldn't see the undertow beneath the calm surface.
In the original story, Sirius died in the Department of Mysteries at the Ministry of Magic.
The immediate cause was a lapse in combat, an accident born of carelessness. The deeper cause was inevitable: he'd walked into danger willingly to protect Harry.
His death wasn't without meaning, but its meaning was small.
It wasn't a chosen sacrifice. It was a tragic accident.
If he'd been stronger, more tactically aware, more cautious in his judgment, the outcome might have been different.
Regulus didn't want to see that ending.
Even if Sirius chose to stand against the family, chose to fight for his beliefs and his friendships, Regulus wanted him to have the strength to survive it. To come out the other side alive.
So: beat it into him. Let him taste what real power felt like. See if something stirred.
Regulus looked at Sirius without a word. He walked to the far corner of the training room, stopped ten feet from the wall, and turned around.
Sirius moved to the opposite corner.
They bowed. Wands raised to their chests, a slight dip of the head.
Orion's voice came from the side: "Begin."
He retreated to the wall, leaned back against it, and folded his arms.
Watching his two sons in the ring, he allowed himself one sliver of hope. One in ten thousand.
What if?
What if Sirius was like Regulus? What if there was some hidden depth of talent buried under all that rebellion, just waiting to surface?
He'd mentioned this to Regulus once, quietly, and never brought it up again. Asking twice would make him seem foolish. Desperate.
But standing here now, watching Sirius, he couldn't stop the thought from creeping back. What if?
In the ring, Regulus didn't raise his wand. Didn't take a fighting stance.
His right hand held his wand loosely at his side. His body was relaxed, as though he were out for a stroll.
He stepped forward. Toward Sirius. One step, two steps, his footfalls so light they made no sound at all.
Sirius dropped into a textbook dueling stance: left leg forward, right leg back, center of gravity low, wand raised level with his shoulder, tip aimed squarely at Regulus's chest.
He could see that Regulus had no intention of attacking first. Wasn't even planning to use his wand. The feeling of being underestimated sent a hot spike of anger through him.
"Stupefy!"
A bolt of red light shot from his wand, streaking straight for Regulus's chest.
Regulus didn't dodge. Didn't block. The red light struck the air an inch from his body, burst into a spray of sparks, and dissolved.
A faint silver shimmer passed across his torso, like a ripple spreading over still water. It appeared for an instant at his chest and vanished.
The ripples of a Constant Protego absorbing an attack. But the defense was so strong, or the attack so weak, that the ripple was barely visible at all.
Sirius gritted his teeth and kept casting.
"Rictusempra!"
"Expelliarmus!"
"Incendio!"
"Diffindo!"
"Flipendo!"
Five spells in rapid succession, different colors, different trajectories, converging on Regulus from multiple angles.
Regulus kept walking.
Red, blue, orange. The spells struck him like raindrops hitting a windowpane, scattering tiny sparks before winking out of existence.
An occasional flicker of light rippled across his body, but his clothes didn't so much as wrinkle.
Sirius's face burned red. He'd never seen anything like this.
His opponent hadn't even raised a wand. He was just walking forward behind some unknown protective spell, absorbing everything thrown at him as though Sirius's attacks were less bothersome than gnats.
Fury, Shame, And disbelief. Regulus has gotten this strong?
He even lifted his wand to eye level and examined it, half-suspicious. Was this a fake? Had Kreacher switched it out to let Regulus put on a show and humiliate him?
He shook off the absurd thought and kept casting.
Heavier spells this time.
"Confringo!"
The curse struck the air in front of Regulus and detonated in a bloom of fire and concussive force. Regulus stood at the center of the blast. Not a hair out of place.
"Expulso!"
A stronger explosion curse. The air warped half a meter from Regulus's body, the shockwave visible to the naked eye.
Same result. His stride didn't falter.
"Diffindo!"
A silver arc of light sliced through the air, angled at Regulus's throat. It hit the barrier with a sharp, grinding screech.
Still nothing. The spell held for half a second, then shattered into points of light.
By now, Regulus had closed to within three steps.
He'd seen enough. He had the measure of Sirius's ability. There might be some hidden reserve, some limit-break potential buried deep, but the fundamentals were what they were.
A strong second or third-year at Hogwarts. Not even top of that range.
And Sirius had planted his feet and fired from one spot the entire time. No footwork. No repositioning at all.
Talent wasted to this degree was almost offensive.
Regulus stopped holding back. His stride quickened, two steps eating up the last three meters, and he was standing in front of Sirius.
Sirius's face was flushed dark with anger and shame, the hand gripping his wand trembling. He glared at Regulus with something feral in his eyes.
Regulus met them. The same grey irises as his own, but right now they were ablaze. Burning with frustration, with wounded pride, with the raw, unspoken demand: How dare you do this to me?
Regulus's expression gave back nothing.
"Is that all?" His voice was flat.
Sirius's breath caught. The distance between them had collapsed to almost nothing, too close to even raise a wand.
He wanted to snarl something back, wanted to tell Regulus not to look down on him. The words jammed in his throat, and not one of them made it out.
Regulus didn't bother with magic.
His left hand slipped under Sirius's right arm, palm pressing against the ribs below, and he drove forward.
"Ngh..."