Sirius Black didn't hear the first explosion.
Or the second.
Or even Cassius's opening spell for that matter.
Because the moment his eyes locked onto the hunched, trembling shape of Peter Pettigrew across the clearing—
—everything else vanished.
The air.
The forest.
The shouts.
The magic.
Gone.
All that remained was the traitor.
The man who had effectively murdered James Potter's parents, people who had been more of a family to him than his very own mother and father, as surely as if he'd swung the wand himself.
The rat.
Peter blinked at him with watery eyes, lips quivering in something between fear and pathetic pride.
"S–Sirius, I—"
"Don't," Sirius growled.
His wand snapped up.
Pettigrew flinched so violently he nearly swallowed his tongue.
Good.
Fear was a start.
But not nearly enough.
Peter stumbled backward, trying to raise his wand with shaking fingers. "Y–You don't want to do this, Sirius. We—we were friends!"
Sirius laughed.
It wasn't a healthy sound.
"No, Peter. James and I were friends. Remus and I were friends. You—"
His wand slashed the air.
"DIFFINDO!"
A red arc snapped toward Peter's face.
Peter squealed, throwing up a half-formed shield that cracked like cheap glass.
The spell tore across his arm, slicing fabric and skin.
He screamed.
Sirius inhaled that sound like it was sunlight.
"You," Sirius continued softly, "were always a parasite."
Peter backed into a tree. "S–Sirius, please—!"
"DEPULSO!"
The blasting charm picked Peter up and hurled him ten meters across the clearing.
He hit the ground with a wet thud that made even Sirius wince.
"Get up," Sirius growled. "We're just getting started."
Peter groaned, rolling onto his stomach.
"Sirius—Sirius, you don't under—"
"RISPOSTA!"
A whip of blue force lashed Peter across the back.
He shrieked and spasmed.
Sirius walked toward him slowly, like a predator savouring the last steps.
"You murdered them."
"I–I didn't! Vold—Voldemort—"
"You," Sirius hissed, stopping inches away, "opened the door."
His wand pressed beneath Peter's chin.
Peter whimpered.
And for a moment—somewhere deep inside the ruins of Sirius's sanity—there was the faintest echo of what they used to be.
Four boys.
Four friends.
Four idiots who thought the world could never fall apart.
But it had.
And Peter had been the one to tear it open.
So Sirius shoved the memory away and snarled, "Run."
Peter blinked. "Wh—what?"
Sirius stepped back, wand still aimed at his throat.
"Run."
Peter trembled. "Sirius, please—"
"RUN!"
Pettigrew scrambled to his feet and bolted into the trees.
Sirius smiled—a feral baring of teeth.
Then he sprinted after him, this singular fleeting act of mercy was the last he would give his former friend, before catching him and sending him to the afterlife to live in eternal hell for his sins.
~
Peter crashed through branches, breathing like a man drowning in air.
Sirius stalked behind him, wand flicking lazily.
"STUPEFY."
A red jet of light hit the tree beside Peter, blowing bark apart in a shower of splinters.
He squealed and veered left.
"Wrong way," Sirius called.
"FLAMMA LINEA!"
A line of fire erupted at Peter's feet, forcing him to leap sideways.
He tripped.
Hit the ground.
Scrambled up.
Kept running.
Always running.
Just like he had the night of the attack.
Sirius's heart thudded like a drum in his skull.
He had dreamed of this moment for years.
Revenge.
Justice.
Something to swallow the ache that never left, as a piece of his heart had been wrench away from him.
And now—
Now he intended to enjoy every second.
"James would be laughing," Sirius called after him, voice sharp and broken. "He always said you'd bolt before a fight."
"STOP!" Peter sobbed.
"Make me."
Another spell cracked through the trees.
"OSSEO FRACTUM!" — a brutal bone-shattering curse.
Peter dove, screaming, as it shattered a boulder into dust.
Sirius laughed again.
The bad kind.
"Peter," he sang. "Oh, Petey…"
He raised his wand.
"Don't hide. I can smell cowardice."
And then—
Peter made the stupidest mistake of his life.
He turned back.
Just a glance.
Just a look of pure, animal terror.
But Sirius saw it.
And he saw the glint of something else—
Peter's hand shaking above his wand, not with courage, but with calculation.
He was about to transform.
Sirius snarled.
"No you don't—"
But he was a second too slow.
Peter shrieked, "FUGAMUS!" and exploded into gray fur.
The rat hit the ground running.
Sirius's wand lit the forest.
"INCARCERUS!"
Ropes snapped toward the rodent but missed by inches.
Peter darted into the undergrowth.
Sirius exhaled once—long and shaking.
Then everything inside him dropped away.
His bones twisted.
His vision sharpened.
The world tilted.
And with a sound like ripping cloth—
Padfoot landed on four paws.
The great black hound bared his teeth in silent fury.
Peter was small.
Fast.Slippery.
But Sirius?
Sirius had hunted with Remus for years.
Hunted bigger prey.
Smarter prey.
Prey that fought back.
Peter was nothing.
Padfoot launched forward.
The forest blurred around him.
He could smell the rat—fear, sweat, tears, blood, cheap cologne, stale pastries.
The scent trail was thick and panicked.
Padfoot's muscles coiled.
Faster.
Faster.
The rat zigzagged through roots, dove under a log, scurried around a tree—
Padfoot barreled through the tree.
Bark exploded.
Peter squeaked.
Padfoot chased.
Fangs snapping inches behind the rat's tail.
Peter darted up a fallen branch—
Padfoot crushed it under his weight.
He was getting closer.
Peter veered around a rock—
Padfoot leapt over it.
Peter dove into a hollow stump—
Padfoot slammed it sideways and scattered the wood like matchsticks.
For the first time, Peter understood—
He wasn't escaping.
He wasn't tricking.
He wasn't bargaining.
He was prey.
And Sirius Black was the predator he deserved.
Peter darted into a narrow crevice between two stones.
He squeezed through, trembling so hard he nearly wedged himself permanently.
Padfoot skidded to a stop.
Golden eyes glowed in the dark.
A low rumble built in his throat.
Not a growl.
A promise.
Peter squeaked, stuck halfway through.
He kicked uselessly, claws scratching at stone.
Behind him, Padfoot sniffed.
Measured.
Judged.
Then stepped back three paces.
Peter froze.
Padfoot rushed forward.
He slammed into the stones with such force that the ground shook.
Peter screamed—high, sharp, terrified.
The rocks cracked and shifted.
The rat tumbled out the other side, dazed—
Padfoot was already circling.
Peter tried to run again—
Padfoot clipped him with one paw, sending him tumbling head over tail.
Peter squealed, rolling until he hit a tree root.
He shifted back into human form, gasping in terror, clutching his chest.
"PLEASE!" Peter sobbed. "SIRIUS—PLEASE—DON'T—!"
Padfoot shimmered—Bones reshaping—Limbs twisting—And Sirius Black stood over him again.
Eyes hollow.
Voice low.
"You killed them."
Peter shook violently. "I—I didn't want—"
"You killed them."
"Sirius—please—mercy—"
Sirius crouched, face inches from Peter's.
"Mercy," he whispered, "is for men."
His hand closed around Peter's throat.
"You stopped being one the night you chose him over us."
Peter sobbed, choking.
Sirius squeezed tighter.
Not enough to kill.
Not yet.
Just enough to make him understand.
"This is hell, Peter," Sirius murmured. "And you earned every step."
Peter clawed weakly at his wrist.
Sirius didn't let go.
Not until he heard footsteps crashing toward them—Remus's steps, Snape's robes snapping in the wind.
Only then did Sirius release his grip and shove Peter forward into the dirt.
And Sirius smiled.
Because for the first time in years—
He felt whole.
He had well and truly lost a friend he once held dear but he had never felt more satisfied claiming a revenge that was rightfully his after so many years.