Regulus Black was a spy for the Order. He had been a spy for two years, dutifully passing information onto Dumbledore and going on highly secret missions for intel, noting down everything he had seen or heard in a heavily warded journal. He had only suspected that Voldemort was using Horcruxes to make him invincible and immortal, he certainly was arrogant and insane enough to try it. Not to mention the way his face had evolved into something of a monster throughout the war, with bright pupil-less red eyes and smoothly stretched grey skin across his face. When Regulus had met him two years ago, at 16, Voldemort had looked entirely and ordinarily human, a middle-aged man who was slightly balding with sharp features and piercing eyes. He looked like a dark creature now, something unclassified, his own race. The tomes in the Black Library in Grimmauld Place about ancient dark magic and forbidden rituals had nearly confirmed it for him, but the night that Voldemort took Kreacher on a mysterious expedition was the night it was truly confirmed for him.
Kreacher apparated into Regulus’ room with a loud crack, water dripping off his large ears, and a bloody cut on his cheek. The elf was hysterical, eyes wide and pupils dilated with fear, wringing his small hands and taking haggard breaths. Regulus set down his mug of tea haphazardly, sloshing earle grey over the sides as he rushed over to Kreacher, crouching before him and searching for injuries.
“What happened? Did he hurt you, Kreacher?” The distressed elf made a high-pitched noise in his throat, shaking his head, eyes darting around Regulus’ bedroom like he expected Voldemort to pop out of the closet at any moment. Regulus had never seen him more upset in his life, not even when Sirius ran away, or when Regulus broke his leg falling down the stairs as a child. He felt a little bad about it, but Regulus figured the best way to cut through the elf’s panic was to give him an order, something to hold onto. “He’s not here, Kreacher. I order you to calm down and tell me what happened.”
Kreacher’s spine snapped straight, the loyalty magic that bound house elves to their masters sparking within him. The elf bowed his head, shoulders still shaking tremulously although he was more steady when he straightened, croaking his answer, “The Dark Lord took Kreacher to a dark cave, and used Kreacher’s blood to open it. There was an island surrounded by black water and evil that lurked and moved inside the depths,” Kreacher tugged on his ears, his creaky voice rising in volume as he worked himself up again, “He ordered Kreacher to drink a terrible potion, a-and it made him see things…”
Regulus shifted his eyes away from the elf’s haunted face, pretending not to see the way his eyes filled rapidly with tears as he described the agonizing effects of the potion. He stood up, pacing the length of the room, taking in the information presented to him. Regulus wasn’t familiar with the potion Kreacher described, scanning his brain for possible cures in case it was deadly or had lasting side effects. He stopped in his tracks when he began to describe the locket Voldemort had placed in the basin, summoning his journal and a quill, and scratching down every detail.
“You did well, Kreacher, this is exactly what I need,” Regulus praised, looking up from his journal briefly to smile at the elf. Kreacher looked appeased, further calming with the approval. “I need you to do something else for me,” He steeled himself, meeting his eyes with grim determination, “I need you to take me to the cave.”
Kreacher had burst into tears as soon as the words left his mouth, and Regulus grimaced, not surprised but still feeling guilty for it. He threw himself at Regulus’ feet, begging him not to force Kreacher to take him back there. Regulus knew it was cruel, after everything Kreacher had gone through, to make him go back on the same night, but he also knew Voldemort wouldn’t return after just visiting, and it might be his best chance to steal the Horcrux. Killing Voldemort mattered more than Kreacher’s feelings, he tried to remind himself, mentally making a note to make it up to him somehow later.
~
Kreacher begged Regulus to let him take the potion, pulling on his wrist insistently to try to draw him away. But Regulus had put Kreacher through enough, he wasn’t about to subject him to it again, forcing him to come back to the cave was bad as it was. He tried every spell he could think of first to vanish the potion or pour it out, but it remained unchanged in the basin, full to the brim no matter what he did. The only option was to drink it. Regulus stared down at the potion, it looked completely harmless, just like water, but he could only imagine the agony it would bring when drunk. He selfishly wished that Sirius were here, Sirius, his brother who always laughed too loudly and made everything seem a little less scary, no matter the situation. Or James, who could instantly make him feel safer by putting his arm around him, who made him feel like nothing bad could possibly happen while they were together, grinning like lovesick fools. Oh, this was so stupid, he thought. Gathering his courage, he grabbed the shell on the side of the basin, eyeing his reflection warily.
“Kreacher, you don’t need to stay for this part. I’ll be home before long, I don’t want to subject you to this any longer.”
“Master Regulus cannot leave the cave without Kreacher, only a house elf can apparate out, and Kreacher is not leaving Master Regulus alone,” He said firmly, his face set determinedly, despite the way his small form shook. Of course, Regulus thought, Voldemort would make the cave inescapable, so even if the Horcrux was found, no wizard would be able to leave, and no wizard would think to bring a house elf with them.
Regulus sighed, turning to look at the elf, “Alright, Kreacher, you have to do exactly as I say then. When I drink this potion, I might lose my mind and beg to stop. It’s your job to make sure I keep drinking it until it’s all done, no matter what I say during or afterward. If I tell you to leave me and take the locket, you listen and bring it straight to Sirius or James, tell them what you told me, and give them my journal. It’s charmed so only they can open it if something happens to me. Understand? These are all orders, you must listen to me.”
“Kreacher is listening to Master Regulus, Kreacher promises.”
Regulus nodded, turning back to the potion. He took the first gulp before he could think about it any longer, swallowing thickly, the potion left an acrid taste on his tongue. Nothing happened until about the fourth swallow, his vision had started shaking, making him see double and triple everything. Regulus hadn’t realized he was on his knees until three Kreachers came into focus, eye-level with him instead of at his elbow. It was like he apparated away, in the cave one moment, and the next, he was on the floor of the drawing-room, Walburga’s screams echoing in his ears as if she were right behind him. He was staring down at Sirius, covered in blood and writhing on the floor in pain, flashes of red igniting the room. Regulus could see himself at 14, kneeling over his brother and trying to heal him with rudimentary healing spells, begging him to stay home even though he knew Sirius would die there.
"S'il te plaît, Sirius, ne me laisse pas ici," Regulus ached with the desperation laced in his voice, his selfish desire to keep his brother who had selflessly defended him his whole life, in a home where his mere existence was despised.
Regulus choked on it, his selfishness and cowardice as he watched himself then at 16, taking the Dark Mark, reliving in perfect detail the way it burned and writhed on his arm, the sense of utter wrongness that became a part of him forever. The way Sirius and James had looked when he’d shown them, Sirius spat at him and left without a word, not waiting or caring to hear an explanation. The way James had stood there, outwardly sobbing, only asking him one question, ‘Why? Why would you do this?’
It was like watching a highlight reel of his worst moments, his biggest regrets, his fears, and every way he’s failed as a friend, brother, and boyfriend. His vision flitted between memories and reality, occasionally clearing enough to see Kreacher’s face offering him another swallow of the torture potion. Regulus couldn’t tell if he was screaming, crying, or anything at all. He couldn’t feel his body and he couldn’t hear anything over his mother’s shrieks and James' sobs, the memories melting together and running over each other.
“Master Regulus must drink more! Just one more left, he ordered Kreacher to,” Kreacher croaked and Regulus shook his head vehemently, drawing back from Kreacher’s outstretched hands. Kreacher followed him, repeating himself until Regulus opened his mouth again, accepting the potion through glassy eyes, his face streaked with tears.
Kreacher turned, eagerly making his way to the basin to grab the locket, holding it out for Regulus to see. Regulus, who was halfway bent over the still black water, attempting to cup some in his shaky hands to quench his thirst. “No! The water has hands! Master-” Kreacher yelled, nearly fumbling the locket entirely when a skeletal hand lurched out of the black water, wrapping itself around Regulus’ wrist and yanking him towards the water.
Regulus teetered, fighting not to lose his balance, slipping on the slick tiles. Kreacher slipped the locket around his neck and stumbled across the island urgently, fingers ghosting the back of his robes as he tried to get a solid grip on Regulus while he thrashed in panic. Regulus fumbled for his wand, one wrist still locked in the rubbery hand’s grasp, but his mind was addled, and he was disoriented, making his movements more uncoordinated as he slipped closer to the water. Kreacher could do nothing as two more hands appeared, yanking Regulus further down until his head disappeared underneath the surface of the water with a yelp and a loud splash. Kreacher screamed again, scanning the surface for Regulus but seeing nothing, useless without a wizard’s powers, terror encompassing him as he apparated away to the only people he knew would be able to help.
Sirius and James were playing exploding snap in James’ room when the frantic house elf appeared between them, a strange-looking locket around his neck. “Kreacher is needing your help! Kreacher is needing it right now!” He clamped a bony hand around Sirius' wrist, pleading with him with large, tearful eyes. James looked just as baffled as Sirius, meeting his eyes over the hysterical elf. “It’s Master Regulus! He is needing help!”
Sirius’ eyes snapped to Kreacher’s, eyebrows scrunching in worry, “Reg? Where is he? Is he hurt?” He asked each question in rapid succession, barely breathing in between them.
“There is no time! Master Regulus is trapped under the water!”
“Take us there, Kreacher, right now!” James interrupted, swallowing his own questions and grabbing Kreacher’s other free hand. Instantly, he apparated them to a dark cave, illuminated by an eerie green light that floated over still black water, the entire cave so silent that every drip from the ceiling could be heard.
“Where is he? Where did he fall in?” Sirius questioned, stepping towards the water and leaning over for a better look.
“The water has hands! They pulled him under right there,” Kreacher responded, pointing to a wet spot on the tiles. Sirius picked up a shell next to the basin, tossing it into the water and stepping back in shock when multiple clawed hands snapped up to grab it, scrabbling for the shell before abruptly settling, the water becoming still and glassy again.
“Inferi,” James breathed, “The inferi pulled him in. Hey-” He grabbed Sirius’ bicep as he stepped closer to the water with single-minded focus.
“Reg’s in there, I have to go get him!” Sirius exclaimed, trying to shrug off James' hand.
James held firm, tightening his grip, “You can’t swim, you prat. Look, fire draws them away, right? Cast an incendio while I get him, they should leave us alone then.” James advised, eyeing the water anxiously. He pulled Sirius further away from the water, releasing him and taking his place, stepping down so the water barely met his shoes.
“Be careful Prongs, and bring my brother back.” Sirius waved his wand in an arc over his head, “Incendio!” He shouted, orange and red fire exploding from the end of his wand, encircling the entire island around them.
James tightened his grip on his wand, taking a deep breath before diving into the dark water. He cast a wordless lumos from his wand startling when he noticed the sheer amount of bodies in the lake, throwing themselves away from the flames that cast orange light over the surface of the water. James scanned the water around him again, casting out his wand light as far as it would go until landed on a dark head of hair, Regulus. There were at least three inferi clawing at him, tearing his robes to shreds and digging deep lines into his flesh, tugging him further into the depths. Regulus' eyes were closed and his arms drifted above his head, seemingly oblivious to the inferi clawing him to death. James shot a burst of white light towards him, making the inferi screech and swim away in their panic, leaving a battered Regulus behind. James put his wand between his teeth and swam down towards his boyfriend, latching his arms around his waist and kicking up as hard as he could, his chest burning fiercely from the lack of air.
He dragged them up through the water, gasping when their heads finally breached the surface, Regulus' head lolling back as James struggled to keep them above water. Sirius staggered towards them, trying to maintain his balance as he brought the fire closer, warding off any lingering inferi. Kreacher wrung his hands out over and over, muttering under his breath as he watched the scene unfold. James reached blindly for a handhold to help pull them up, straining with Regulus’ dead weight and only managing to bring them halfway out of the water. Sirius canceled the spell, grabbing his brother under the arms and pulling him onto the island as James crawled to collapse next to him, trying to get his breathing under control. Regulus’ lips were a dark blue, and his skin was stark white, other than the scarlet blood flowing from multiple wounds on his body.
“Kreacher,” Sirius panted, still gripping Regulus' limp body, “G-Get us out of here, now! ”
They landed with a thump on the floor of James’ bedroom a second later, Sirius lowering Regulus to the floor carefully, “Grab bandages and blood-replenishing potions, lots of them,” He ordered the elf without looking at him, patting his brother on the cheek lightly, trying to rouse him while James scrambled to find a pulse.
James jabbed his fingers into Regulus’ neck, fingers sliding against damp skin, “Come on, love,” He murmured under his breath, pressing down harder and closing his eyes to help him concentrate better. “I can’t, I can’t feel anything, Sirius,” James bit back a sob, opening his eyes, fingers brushing at his boyfriend's blue lips, searching for a sign of life, at a loss for what to do. The hardwood floor beneath them turned red and slick with blood.
Sirius squared his shoulders, taking a deep breath to steady himself, “Okay, okay. Lift his chin, and when I tell you, cover his nose and breathe into his mouth,” Sirius instructed, pushing James away from his brother, and forcing him to sit back on his heels. Sirius positioned himself above Regulus and placed his hands in the center of his sternum, glancing at his terrifyingly slack face. James watched him in awe and confusion as he began to push down on Regulus’ chest, pumping rhythmically, and counting aloud. He nodded to James, who startled into action, inhaling deeply before breathing into Regulus’ mouth, noticing his chest rise with the motion. Sirius’ breath was ragged as he worked, his face burning red with the effort of forcing his brother’s heart to beat while his best friend breathed for him. The only sounds in the room were Sirius' breaths and counting, along with James' muffled whimpers.
“Please Reg,” James pleaded in between giving breaths, one hand still resting on the pulse point at his neck, “Breathe, you have to breathe,” He could tell Sirius’ strength was flagging, but he was relentless, even as the minutes passed and he remained unchanged, Sirius was unwilling to let his only brother die in front of him. James’ lungs were burning with the effort, but they kept going, working in tandem as the minutes passed. James was about to give another breath when Regulus shot up with a choked gasp, a hand clutching at his throat, nearly head-butting James in the process. Water burst from his lips as he choked, wheezing in broken breaths, his grey eyes hazy and panicked. Sirius grabbed his shoulders and pressed him back down into the floor, rolling Regulus onto his side and pounding on his back to get the rest of the water out. James pulled Regulus’ freezing hand away from his throat, squeezing it in his own, “You’re alright, you’re alright, we’ve got you, love. Get it all out,” He soothed, brushing damp hair out of Regulus’ face as he coughed up all the water he ingested, trying to clear his lungs and get a solid breath in.
“Slow down, petite étoile,” Sirius said softly, his voice cracking with emotion, rubbing between Regulus’ shoulder blades carefully as the coughing slowed gradually, avoiding the places he was wounded, his heart breaking as his brother curled in on himself, choking on every inhale and exhaling too fast, “Breathe slowly, it’ll get easier,” Sirius promised. Regulus’ eyes were bloodshot and heavy-lidded, he did not respond, but he made an effort to focus on slowing his stuttering breaths, squeezing James’ hand weakly to prove he was there.
“Good, love, you’re doing so well,” James praised, pressing the hand not intertwined with Regulus' to his chest and watching intently as it rose and fell with every shaky breath, needing to see the movement. James blanched when he noticed the blood seeping through his fingers, suddenly aware of how much blood he was kneeling in, “Sirius, he’s losing too much blood,” He said urgently, pressing down harder on one of the biggest wounds, crisscrossed claw marks overlapping on his chest. Regulus gagged, overwhelmed with the sudden burst of pain that tore its way through his chest.
Kreacher popped back into the room, small arms full of potions and supplies as Sirius tore the remaining shreds of Regulus’ robes away frantically, revealing the long jagged claw marks that marred his arms and torso. Regulus shivered as damp skin met the cool air, wet hair dripping water down his back as rivulets of blood slid down his arms and torso.
“Merlin, Reggie, what the hell,” Sirius whispered, the full extent of his injuries looking much worse without any covering.
He muttered healing spells under his breath, listing every one he could think of, cursing colorfully when the wounds refused to stay closed, though the blood flowing from the wounds had slowed. Magical wounds, specifically from dark creatures, couldn’t always be healed by magic. Kreacher, who had taken care of the Black brothers' injuries most of their childhoods, took charge with ease, rushing forward with a small brown bottle clutched in his small hand. He used the essence of dittany to drip small amounts into every gaping scar, the skin stretching and pulling on both sides to close the wounds. He hummed a French lullaby under his breath while he did so, trying to calm Regulus with something he had sung for both brothers when they were little.
Regulus moaned in pain, half-conscious but too exhausted to do much more than that, occasionally squeezing James’ hand and curling his body protectively around their linked hands. Sirius followed after Kreacher’s ministrations with murtlap essence, falling into a familiar rhythm, using the same gunk they used on Moony’s scars after he ripped them open on full moons, wrapping bandages around the treated wounds. James helped them lift Regulus into a sitting position so they could wind thick bandages around his body, leaning him slightly against James so he remained upright.
Through all this, Regulus had been silent, never fully unconscious again, but never fully there either, allowing them to move him however they needed, time passing around him sluggishly. He imagined he was dead and dreaming of Sirius and James rescuing him, or that he was stuck in the cave still, merely experiencing the effects of the potion. But every time the thought crossed his disoriented mind, he saw the locket swinging around Kreacher's neck, reminding him that he did get out, somehow.
When they had finished, leaving Regulus looking like a mummy, Sirius and Kreacher left to wash their hands free of all the blood, leaving James and Regulus alone for a moment. Regulus slouched into James bonelessly as he pulled him further onto his lap, vanishing the blood that pooled on the floor with his other arm wrapped around Regulus’ waist. James pressed a lingering kiss to his temple, smelling the salt in his hair, still slightly damp from the water and curling at the ends.
“Alright, love, I need you to take these potions for me,” James said, nudging him lightly. “You awake?” He added, glancing down at Regulus when he didn’t respond. His face was drawn and pale, and his eyes were closed, but his breathing was steady and his lips were turning pink again, still tinged with blue on the edges. Regulus hummed an affirmative and nodded slightly against his boyfriend's shoulder, not using any more energy to speak. James grabbed the potions, supporting Regulus’ head with one hand and feeding him several for blood-replenishing and pain. Regulus sighed in relief, dropping his head back on James’ shoulder, slipping his hands under his shirt, and burrowing closer to absorb some of his warmth.
James hissed at the sensation, “You’re absolutely freezing, darling,” He cast a warming and drying charm on the both of them, rubbing his hands up and down Regulus' arms to warm him up.
“‘M sorry,” Regulus mumbled, the first words he’d said all night, barely audible with his face tucked into James’ neck.
“What are you sorry for, love? You haven’t done anything,” James asked after a beat, concern still bleeding through his tone.
“For going alone,” He answered, still shivering slightly, unable to stop the trembling that was wracking his body.
James halted, mid-movement, asking the question he knew had been bouncing around his and Sirius’ minds all night, “Why did you, love?" He pulled away slightly to look at Regulus' face, frowning when he hesitated to answer, adding, "Did Dumbledore make you?”
“What did Dumbledore make you do, Reggie?” Sirius demanded, stepping through the door with Kreacher on his heels. He hated the way Dumbledore used his brother, and was endlessly suspicious of his intentions. “Did Dumbledore send you on this death mission?!” Protective brother instincts kicked in, anger already twisting his features.
Regulus rolled his eyes, shifting slightly to look up at his brother, “No, he didn’t, I sent myself,” He admitted hoarsely, feeling James stiffen beneath him with shock.
“Why would you-” Sirius began agitatedly, his hands carding through his messy hair, "Tu vas me tuer vraiment,"
“Kreacher, do you have the locket?” Regulus ignored his brother's dramatics, sitting up in James' arms and extending a hand to the house elf. Kreacher nodded, walking towards him and dropping the locket in his hand with a bow. Regulus took a deep breath, “This, is a Horcrux…”