[Rating is for blood, violence and a brief mention of cannibalism]

School: Hogwarts Year 2

Theme: Borgin and Burkes (Explore characters who need dark magic to survive or as their occupation)

Prompt: Horror [Genre] (main); Regulus Black [character]; Turncoat [Character Type];

WC: 2900

"Mr Black?"

Sirius started, guilt washing through him, twisted and full of thorns. His gaze moved up jerkily as different objects seemed to imprint themselves on his mind: the edge of the table, dark varnished wood pitted with the imprints of a thousand nails; a glass of water, fingerprints marring the slick film of condensation, a single bead running down the side like a tear; the interviewer's badge, the twisting symbol almost seeming to shift as she leant forward expectantly.

"What was the question?" he croaked, running one hand reflexively along the scratch of stubble along his jaw, biting back a yawn. He froze, bile rising in his throat, and returned his hand to his lap, clasping them together tight enough that his bones creaked. He didn't look down.

The woman—Miss Sabine Barlow if Sirius was remembering her name correctly; his thoughts were slow and muddled as exhaustion wormed through his mind—sat back in her chair, lips thinning slightly.

"What prompted you to explore the crime scene?"

"That wasn't a crime scene. It was a massacre."

Sabine nodded slowly, a spark of anger flickering and then dying in Sirius' chest. He was so tired, too tired to maintain any form of anger at her smug attitude. She wasn't there, she didn't see.

"If we could go from the beginning, for the record?"

Sirius nodded, throat bobbing as he swallowed compulsively again and again.

"It started just at the end of shift."

"Sirius?"

The coffee was bitter, the milk carrying with it an almost sour taste, but Sirius gulped it down regardless. His footsteps echoed back at him as he hurried back towards the main office. Some part of him knew that daring to prepare for five minutes of peace would summon some sort of calamity from the Aurors on patrol, but they had been on alert all night and nothing had happened.

James waved him over for a fraction of a second before he was forced to steady himself on the railing, feet kicking out into the air as he tipped forwards into the pit—

Sirius couldn't remember crossing the room, but James was heavy as Sirius latched on his ankles, heavy boots slamming into the railing as he pushed himself to the ground. The wind was knocked out of Sirius by the impact, and further knocked out of him as James landed on top of him, stars dancing in front of his eyes as he struggled to draw in air.

"Sorry mate. You alright?"

Sirius could barely do more than cough, a deep hacking thing that robbed him of any breath he retained, but he managed to flip James off as the other man hopped back onto the railing.

"Something's wrong with the Stone."

The Stone wasn't the official name for the huge monument that dominated the centre of the Auror Office, but it was the one everyone used since it's installation in a bid to improve the communication from Aurors in the field. Lily had compared it to Muggle walkie-talkies when she first heard of it, and—after an extensive explanation and an afternoon of chasing James round a field—Sirius was inclined to agree. Sirius tilted his head, idly tapping his fingers against his lips, and studied the swirl of colours on its surface. The normally blank surface was a riot of colours, some of which Sirius had never seen before.

"Have you tried connecting yet?" he asked James, who was shaking his head before Sirius even finished the sentence.

"Wanted some back up, just in case—"

James let the end of the sentence trail off into the silence, and Sirius sighed, feeling the pull of sleep for a precious few seconds, before he nodded. This was going to be a late shift.

"Okay."

James shifted, glanced back at Sirius, and tapped the runes carved into the podium to activate the Stone.

The world erupted into screams.

Sirius dropped to his knees, clamping his hands over his ears, but it did nothing. They just kept screaming.

It could have been hours, it could have been days. There was nothing but the screams, nothing but the sound of unconstrained agony.

When the screams stopped, the silence was so loud Sirius' ears rang with it. He looked up—everything hurt, teeth clenched too tight, nails biting into his scalp— and saw James' white as a sheet.

"There was—They—"

James' face was bloody, tears streaming from his eyes and cutting through the mess beneath his now broken nose.

"There was an address. Right at the end," James gasped, fingers twitching as he sunk to the floor, legs too weak to hold him upright.

Sirius knew then what he had to do, cold dread crawling up his spine and threatening to close it's icy fingers around his heart. You never leave without your partner. The phrase was yelled at them almost as many times as Moody threw things at their heads with the aim of 'Constant Vigilance'. But now, as Sirius stared at James' pale face, at his set jaw, Sirius would have to go alone.

Water soaked through his shoes as Sirius ran through the driving rain, screams still echoing in his ears. There was a war raging on all around him. Even if the Muggles didn't know it, they could sense it and the streets were almost empty. Sirius recast the Disillusionment Charm and ran past a Muggle making his slow way down the street. He was slight, swaying and stumbling as he walked, uncaring of the rain plastering his clothes to his skin.

Sirius' boots hit the pavement hard, sound not muffled, but he didn't care. He had to get there, he had to see—

Blood pooled on the steps outside of the safe house, slowly dripping down the slick stone. His gaze followed it back up, tracing the rivulets of it's passage to the door. It was ajar, slightly creaking as it swung, a tiny movement for such a loud noise. Sirius paused, wavering on the edges of the steps as blood hit the edges of his boots, thick and sticky. He shouldn't be here, could go back and report what he saw, get help—

But from whom?

Someone could still be alive in there; he had to see. He owed them that much, at least.

Sirius drew his wand and walked up the stairs.

Iron, hot and thick, assaulted every sense as he stepped inside, wand raised. Blood covered the pale walls, his mind automatically picking out the patterns: a rune here, fresher as the blood had run down the wall; a handprint there—directional, whoever left it was trying to get away. He knew there was no-one alive in this house, knew it with a sickening certainty, but he cast the spells regardless, moving through the motions.

"Homenum Revelio," Sirius whispered, unable to bring himself to break the death like stillness, "Appare Vestigium."

He didn't have time to dwell on the stillness the Human-Presence-Revealing spell brought—stomach dipping as if he was balanced on the edge of a cliff—as the riot of colours that the Tracking Spell created exploded in front of his eyes.

"Red for Auror Skyler Hatch," Sirius muttered. She'd been a short woman, constantly craning her neck to stare her taller colleagues in the face, but she had a wide grin and a crooked nose that spoke to her long career as an Auror. Her trail never ventured up the stairs but instead crisscrossed the ground floor of the two storey house, speaking to her time spent here on guard duty. The brightest trail—the one that tracked her final moments of life—wound it's way from the door to the kitchen. The blood pools marked her path as well.

"Blue for Vernie Rubis." Vernie had a deep, booming laugh; the kind that turned heads and was purely infectious. A face full of freckles and a bright red beard completed his eye catching appearance—an oddity for an Auror to be sure, but it worked somehow. His trail was brightest on the stairs, but Sirius knew it would crisscross the floor above them extensively.

"And grey for Alois Knotts." He couldn't keep the disgust out of his whisper. The weasel-faced man—a known Death Eater with a list of crimes longer than Sirius' arm—had only agreed to testify because he had been caught, not because of any regret he felt following a genocidal maniac. Moody, Sirius knew, held similar feelings, which is why he had placed Rubis and Hatch on guard duty.

Numb feet carried him up the stairs, carefully stepping around the blood smears covering every single surface. If this was the work of the man he was thinking of—and he hoped, he hoped with everything he had, that it wasn't him—then he knew where to find Knotts.

The grey trail passed through the largest blood pools, congealing liquid clinging to Sirius' boots. The heavy tang of iron was stronger up here, coating the inside of Sirius' lungs, clinging to his skin and he feared he would never taste fresh air again.

A shiver ran down his spine, the hair on the back of his neck prickling as he stared at the bedroom door. It was ajar, swaying with the same hollow creaking noise as the front door, and Sirius froze, unable to open it, unable to confirm what he knew lay beyond.

"You signed up for this," he whispered, wishing more than anything that James could have traveled with him. But someone had to stay behind—they couldn't leave the base empty, and Sirius had to see for himself.

Before he could falter again, fear crawling up his spine, Sirius opened the door.

The body that lay in the bed—twisted and malformed, mouth hanging open in a grotesque scream far wider than was possible—was barely recognisable as human, let alone as Alois Knotts. But Sirius knew how this killer operated.

Breathing as shallowly as he dared, head swimming with the effort, Sirius checked his left forearm—the only piece of skin left fully intact—and the Dark Mark stared back at him, coloured a deep, rich black. The heart would be gone, and Sirius turned to check the final clue.

NOT DEAD YET.

Three words, ten letters, carefully transcribed into the opposite wall in Knotts' blood. Those words set these crimes apart from the other accounts of butchery and savagery that passed through the Auror's office. No-one, bar one person, knew who was behind them. Last time Sirius had heard anything, the betting pool was equal between Moody and a disgruntled werewolf.

No-one knew what Sirius knew.

James may suspect something was amiss, but Sirius' reaction hadn't been too out of place amongst the sea of paling faces and groans of horror. James' nails had dug into Sirius' hand so when his own hand tightened on James', it wasn't out of place.

He could be wrong. Sirius knew he wasn't, but there was a small chance.

Sirius was lying to himself. He knew that handwriting almost as well as his own.

He knew the characteristic flicks on the edges of the N, the diagonal slash of the T, even the curved E and the spiked A. Sirius had taught Regulus to write after all.

They may have been in different houses, but they were still brothers. Regulus had always taken too much satisfaction in correcting Sirius' essay as they sat in the Hogwarts Library, hidden from everyone who would use their closeness against them. He could spot Regulus' handwriting a mile away.

Regulus was classed as dead. The funeral had been nice, as far as funerals went—and Sirius had been to far too many funerals already.

The man in the street.

Sirius froze. Why had the man in the street returned to his mind? What did he have to do—

Fuck.

Sirius had thought the man was wearing gloves. Everything he had been wearing was dark and gloves wasn't a strange thing to see in this weather. But—as the scene played out again behind his eyes—the man's hands had been bare, instead covered from wrist to fingertip in dark, drying blood.

"You passed by the killer?"

Sirius nodded, secrets piling up on his tongue, threatening to choke him. The interview was a careful dance of truths and half-truths, and now was the dangerous part.

Sabine breathed out slowly, carefully writing down a few more notes in her clear, blocky handwriting.

"My apologies for the interruption. You previously said that you chased him into an abandoned building? Could you continue from there please?"

"Regulus!" Sirius yelled, kicking the door closed behind him.

The Black House was, technically, abandoned. There were several old family homes—and countless smaller homes—that were closed up while the occupants fled for the country, a cycle that repeated itself again and again and again.

Sirius had run after the man he believed—knew—to be Regulus, seeing his shadow pass through the streetlights, always just ahead of him. Was this chase what he had been after all this time? Just to lure Sirius out and then—

He couldn't think further, breath tight in his chest, the wards passing over him like ice, colder than the biting rain outside.

Silence greeted his shout, the house as still and quiet as a grave.

"Hello, Sirius."

Sirius' wand was raised before he could think, hand steady as he levelled it at Regulus' throat. His hood was still pulled up, face hidden in deep shadows, but Sirius' heart skipped a beat when Regulus grinned. For a moment he was a child again, watching some prank inflict havoc at a party, hidden in shadows with Regulus at his side, by his side, on his side.

But the moment passed as quickly as it arrived, and Sirius stepped closer as Regulus stepped backwards.

"Hands up."

He slowly raised his hands, dried blood flaking off onto the floor.

"Are you going to arrest me, Sirius?"

Regulus' voice was strange. It was too low and held an almost raspy quality. Regulus' jaw shifted unnaturally as he spoke, almost as if he was forcing the words out from an unwilling throat.

"You've killed people."

"So have you."

Sirius growled, and Regulus' grinned, the corner of his mouth twisting up to reveal a dark gap where a canine tooth had once been.

"How do you keep finding them?" Sirius barked, stepping closer when Regulus didn't respond, wand almost pressed into the soft skin of his throat. It gave in a way human skin shouldn't and bile rose in Sirius' throat. There was a strange sharp smell in the air, almost like alcohol but just different enough that Sirius couldn't place it.

"Their Marks call to me," Regulus whispered, tipping his head back just enough to meet Sirius' eyes. They were alight with an unearthly fire. "There is nowhere on earth that they can hide from me now."

"Why Death Eaters? You joined up with them. You were one of their best."

It hadn't felt real when James had told him, caught him by the elbow and pulled him into a storage cupboard. Sirius' own baby brother—the boy he remembered as being scared of the dark, who had followed him round like a second shadow—was part of Voldemort's top torturers. He had gone from a young teenager, pale faced and terrified, to a man who killed without hesitation and delighted in the pain and suffering of others. Sirius had lain awake for weeks, unable to clear the horrific images from his mind. And then Regulus died.

"What Voldemort did was unspeakable," Regulus hissed, stepping closer to Sirius until they were nose to nose. His wand sunk into Regulus' throat. He tried to step away, but Regulus was faster. With an inhuman speed, his arms locked around Sirius' shoulders, forcing their heads together, nose to nose, forehead to forehead. And his wand was still in Regulus' throat.

"I betrayed him. And I can't rest until he is destroyed."

Numbly, Sirius realised his own breath was fast and quick, but Regulus didn't seem to be breathing.

"What happened to you?"

Regulus laughed, and tipped his head back fully, hood falling from his head. His skin was the waxy grey of a corpse, heavy stitching crisscrossing a large scar from the corner of his mouth to his hairline.

"Not quite dead, not quite alive," Regulus sighed, exhaling that sharp scent with every word that was forced out of his ruined throat. "You left before you could see the family history, but I stayed. I saw."

"So you're killing Death Eaters."

A nod.

"As a message?"

"As a sacrifice. My fight isn't over yet just because I died."

"How did he lose you?"

"I couldn't say," Sirius said, "I could see him in front of me one second, and then—"

He shrugged, spreading his hands, mindful of the tremors that wracked through them.

"Thank you for your time Mr Black."

Sirius stood to go, cold making his legs uncooperative.

"In your professional opinion," Sirius turned back to look at Sabine, noting the morbid curiosity in her eyes, "What is the killer doing with the hearts?"

Sirius stared back at her. In his mind's eye he could see Regulus, sitting at their kitchen table, his mouth covered with blood as he slowly and methodically chewed and swallowed.

"I couldn't say."