Promise.
Regulus was nothing in his soul if not obsessive. The very core of his being had always screamed more, more, more; and when there was nothing left to feed it, the rotten part of him would dig its claws into the next phase of Regulus’ contemplations, cleaning it out until it was hollow.
It usually started with something exciting. Once upon a time, in the lonely year without Sirius, that had been a golden snitch. He would obsess in the confines of his room, pacing, greedily reading every word of his brother’s Quidditch Through the Ages - once, twice - until he could recite passages in his sleep and he could hear the words in the confines of the night, bouncing from wall to wall in his mind’s eye.
Then, he had spent hours in the air, alone, chasing the snitch. Even when the cold was so biting that his fingers were red and stiff, and his back ached so terribly that he could not lie down. He repeated this routine until he could execute the Wronski Feint without needing to down three vials of Skelegrow. By the start of second year, he was the seeker of the Slytherin quidditch team. By the end, he had won the house the quidditch cup for the first time in 12 years.
See? Obsessive.
Regulus’ obsessions are fruitful, they’re intuitive alongside intentional. He had obsessed over the snitch because it had brought him to quidditch, and the cold, bleak air, purged Regulus of the rot in his stomach.
On the pitch, Regulus was autonomous. On the pitch, Sirius had to confront his younger brother as an equal. On the pitch, Regulus was better. This had been true since that wretched year, and up until this moment in his fifth year.
Regulus was obsessive when it mattered, and years of practice in a Walburgian discipline had meant his mind rarely drifted from his objectives. This was his first practice since returning to Hogwarts, and he should have been fine. His priority in that moment should have been the snitch. Every tackle, and swift manoeuvre, was rehearsed, Regulus knew this all. Yet, every time he closed his eyes all he could see was his elated corpse, winking at him.
He hovered on the pitch for a few moments and when the familiar flash of light buzzed by his face, he let himself barrel towards it before finally encasing it with his hand. He had caught it, but even he knew he was severely slacking. He could do worse, but if he wasn’t going to be fine, he had to commit to the better, so he let the snitch go and chased after it once again. Rinsed, repeated, until he could no longer feel his lungs in his chest. He couldn’t help but feel that every time the cold air whipped against his face, it wasn’t the snitch he was chasing—it was something else entirely.
Something absurd. Something dangerous.
He should have ignored it. He had tried to, really. But the gnawing part of him, the part that could never sit still, was already coiling its claws around the mirror instead of the snitch. It whispered to him, and with a curse to himself, Regulus accepted this absurd proposition. He was to return to the mirror.
The snitch flitted past his face again, a mocking flash of gold. He let his body barrel toward it, forcing his mind back into the rhythm he knew so well. Chase. Reach. Catch. Release. Over and over again.
“Regulus!” A nasally voice snapped him out of his haze, he could barely contain the roll of his eyes as he pulled back his broom abruptly. Why was everyone interrupting him as of late? Maybe he had lost his edge. Nothing about him had changed that drastically besides the small issue of the summer. Had he… become soft?
“Yes, Lestrange?” Regulus allowed himself to adopt a lazy tone, vaguely covering the hysteria that was bubbling in his chest, obsessions clashing with insecurities clashing with any other quandary that his mind had decided to grapple with in that moment. This all seemed to be too much to project onto his team captain; but by the hungry gaze that Rabastan was using on Regulus, he wouldn’t mind scaring the older boy off a little.
“Practice is over. Keep up, yeah?” Rabastan winked at Regulus before flying down onto the grass. Regulus’ stomach turned slightly, the only possible reaction to having caught the eye of Rabastan Lestrange. He groaned before making his way to the changing rooms.
The familiar scent of damp towels and old wood greeted him as the door creaked shut behind him. Regulus let out a long breath—out of the cold, away from the pitch, but not away from the restlessness gnawing at his chest. He was buying time for himself, in a manner most uncouth from the heir of the Most Ancient and Noble House of Black.
“Alright there?” With a turn of his head, Regulus caught sight of Barty crouched in the corner, a half-smoked cigarette hanging out of his smirking mouth. The smoke made Barty’s eyes appear red and strained, but the other boy seemed to not be bothered at all. Regulus made his way over to his friend and took the cigarette from his mouth before taking a long drag himself.
“You can just ask, oh most ancient and annoying Lord Black.” Barty made a bowing motion with his arms, before pulling out another cigarette for Regulus from his pocket. Regulus used his wand to light it, and then leaned his head back against the wall, body aching, and mind racing.
“Rabastan has a bet.” Barty said to the empty space of the changing room after a moment’s silence, shifting his shoulder slightly to nudge Regulus.
“Go on.” Regulus shook himself out of the trance he had put himself in watching the smoke leave Barty’s mouth.
“He bets he can get you to snog him by the end of this year.” Barty cackled.
“How much did you bet?” Regulus smirks at his friend, looking down at his hunched shaking form.
“500 galleons that you’ll snog Rodolphus instead.”
“He is quite pretty, isn’t he. When?” Regulus eyed the other boy.
“By the end of the week.” Barty’s eyes twinkled with mischief.
“Yeah, go on, make it 750 galleons and give me the extra.” Regulus laughed and put out his cigarette in the wall by Barty.
“Hah! I knew you would.” Barty grabbed Regulus’ hands. “You won’t regret this Reggie-poo.” He stared up at Regulus with wide eyes, hands clasping the other boy’s hands between them. “We must tell mother that we have come into a fortune!”
“Mother?” Regulus mused.
“Pandora Rosier.” Barty retorted quickly, almost offended.
“Ah, mother, mais oui!” Regulus snorted.
“Now, Regulus, that isn’t fair, you know what the French does to me.” Barty’s face straightened all at once.
“I’ll save it for Rodolphus.” Regulus moved over Barty to grab another cigarette. He settled, and lit it with his wand once again, watching the smoke pillow in the space in front of him.
“Save what for Rodolphus?” Said a voice looming to the side of them.
James bloody Potter practically strutted into the changing room, wiping sweat off his forehead with a small hand towel, not looking particularly fussed at the sight of the two Slytherins smoking in the space. He looked at the two of them and tilted his head slightly at the conspiratorial smirk that crossed both Regulus and Barty’s faces.
“Monsieur Regulus Black will be defiled by a Monsieur Rodolphus Lestrange by the end of this week” Barty grinned, and James Potter gave Regulus Black the most beautiful sight of his red sputtering face. “Oh Potter! I never took you for a prude, I am disappointed.” Barty faked a frown.
Regulus, on the small chance that this could get back to Sirius, had remained silent. While he was not going to speak to his brother, he was not above occasional psychological warfare, and he knew the imagery was too grotesque for James not to share.
“I, well, I- Regulus?!” James’ eyes were wide as he turned his face toward Regulus mouth agape. “Isn’t he like your cousin, or something?”
“Not yet, but he’s meant to be marrying Bellatrix next year.” Regulus could barely contain his laugh.
“Well, you can’t do that to Si- Bellatrix, you just can’t.” James reasoned, fidgeting with his hand towel as if it could change his situation.
“Si-Bellatrix wouldn’t mind much, don’t you worry about her, Potter.” Regulus laughed at the boy in front of him, who was still very much red in the face. Barty perked up at this.
“Isn’t she with that freak from Ravenclaw, Skitter, or something.”
“Skeeter? Merlin, what the fuck? and for your information I am not worried about Bellatrix.” James pocketed the towel, and now was looking at Regulus and Barty in mild discomfort.
“Oh Jamie-kins don’t tell me you’re a homophobe, that would be so disappointing.” Barty looked at James with a fake pout. “I’ve had a para-social relationship with you for so long, it would be a shame to find out it’ll always be one sided now.”
“I-I’m not? What I-” James covered his face with his palms and groaned. “No, you know what, I’m going.” Regulus almost began crying tears of laughter at the absolute disdain on James’ face.
“See you soon, sexy! Don’t be a stranger.” Barty yelled at the retreating figure of James Potter and then bumped his head with Regulus’ both of them bursting out into a fit of laughter.
“He’s so-” Regulus, began, clutching his stomach keeled over at just how ridiculous James Potter was. Barty suddenly sobered up and turned to face Regulus.
“Sexy.” Barty was completely deadpan.
“Yeah, he is.” Regulus conceded, finishing the last of his cigarette thinking of a sweaty, flustered James Potter. “What the fuck.” Regulus burst into laughter again.
Later, when Regulus stepped into the corridor, leaving behind Barty and the changing room, he would smile to himself thinking of what had occurred, and he’d go red, and sweaty, from the effort of trying to contain his laughter. After floating through Defence, the damp chill of the dungeon was a welcome contrast to the simmering hysteria in his chest.
The classroom was already half-filled when he arrived, a low murmur of conversation rippling through the room. Regulus slid into his usual seat near the middle, where he could avoid both Slughorn’s overenthusiastic comments, and the spittle from his lecturing.
Slughorn’s voice droned on, punctuated by the occasional joke that drew a smattering of polite chuckles from the front row. Regulus’ eyes drifted to the cauldron bubbling at the front of the room, its contents swirling in hypnotic patterns. The words on the blackboard blurred as his mind wandered.
Thoughts of James Potter began to dwindle, as the classroom slowly began to shift and form into the desolate classroom he had been in the week before. With a quiet sigh, Regulus dipped his quill into the ink, jotting down notes more out of habit than interest. Another hour of this, he thought, before he could move on to something that actually mattered.
When he exited the classroom, prepared to make his way to the attic room, he was accosted by a pacing James Potter. He looked at the boy in front of him with slight annoyance, before firmly ignoring him and going on his merry way.
James perked up at the other boy's presence, his face lighting up in a way that made Regulus' annoyance deepen. “Regulus! Right, Reg—wait—”
Regulus brushed past him without another word, his steps quick and purposeful as he headed toward the staircase.
“Regulus! Hey, come on, wait!” James called, scrambling to follow. His footsteps echoed loudly against the dungeon floor, drawing the attention of a few straggling students who glanced curiously at the scene.
Regulus stopped abruptly and spun around; his glare sharp enough to cut through the humid air. “Come off it, Potter,” he hissed, his voice low and venomous.
James skidded to a halt, nearly colliding with him. “Come off what? I haven’t even—”
But Regulus had already turned on his heel, resuming his brisk pace without sparing him another glance.
“Regulus!” James called again, his voice growing more insistent as he jogged to catch up. “Wait, just—can you stop for one second?”
The pair moved through the corridors like this: Regulus storming and James trailing behind, his persistence undeterred. Every few steps, James would call out Regulus’ name, as though saying it repeatedly would somehow compel him to stop.
By the time they reached the narrow staircase leading to the attic, James was huffing and puffing, his hair even more dishevelled than usual from the chase. Regulus, on the other hand, didn’t spare him a second glance, his focus solely on the door ahead.
“Regulus—seriously—just listen to me for—”
But Regulus had already reached the door. He didn’t pause, didn’t respond, didn’t even acknowledge James’ presence as he slipped inside and shut the door firmly behind him, leaving the Gryffindor standing breathless and exasperated in the corridor.
James let out a frustrated groan, running a hand through his hair as he stared at the closed door. “Brilliant,” he muttered to himself, and slipped in behind the raven-haired boy.
“Why would you want to come back here? You were white as a sheet last time, ran out like you saw Peeves.” James made his way to Regulus, who had already unlocked the closet.
“Funny, because all I remember is seeing you.” Regulus quipped back.
“Aww do I make you nervous Regulus?” James was wiggling his eyebrows suggestively.
“Oh, so nervous, there are moths in my stomach.” Regulus deadpanned.
“Right…” James trailed off.
“Actually.” Regulus mused, dragging James in front of the mirror. “Tell me what you see.” Perhaps, the mirror was broken, and Regulus isn’t beyond fucked up for seeing his life’s aspiration being his own rotting corpse. “Tell me what you see.” He repeated.
“Oh, are we that close then?” James smiled at the boy who was standing behind him, hands on his shoulders propping him in place. Regulus snatched his hands to his sides before crossing them over his chest nonchalantly.
James, ever the people pleaser, obliged Regulus. “Well, it’s me, Sirius, Remus, and Peter. We’re in my garden, and my parents are sat having a drink behind us, we’re all laughing. Marlene, and Mary are there too... oh and Dorcas! Ah there’s Lily, this is awesome.” James looked beyond thrilled at the scene in front of him. Regulus sighed. Fuck.
“Why are you swearing.” James snapped his face to look at Regulus.
“I didn’t- Nothing it’s fine.” Regulus sighed, once again, taking his palms and rubbing his eyes until he saw stars, he was going to get some form of dermatitis if he kept doing this.
“What is it, Regulus.” James probed, and in that singular moment of exhaustion, Regulus wonders if he should share with the boy in front of him, wondering what it would feel like to not bare this burden alone for a second.
Regulus’ lips pressed into a thin line. “It’s nothing, Potter,” he said finally, though his voice lacked conviction.
James frowned, the easy smile slipping from his face. “Doesn’t sound like nothing. You’ve got that look—like you’ve swallowed a lemon whole. And then cursed the tree it came from.” Regulus gave an unimpressed look at the figure of the other boy.
“Regulus.” James’ voice softened slightly. “You asked me what I saw. I told you. It’s only fair you do the same. What’s in there that’s got you looking like—well, like that?”
He exhaled sharply, his breath shaky. “Fine,” he snapped, though the sharpness was more at himself than James. “You want to know what I see, Potter? I see myself.”
James raised a brow, confused. “Right, well, that’s—”
“Rotting,” Regulus cut him off. “I see myself rotting. Dead. Bone and decay, like some grotesque parody of what’s left of me. And yet…” He trailed off, his voice faltering, but James was staring at him now, rapt, giving him no room to retreat.
“And yet?” James prompted gently.
Regulus clenched his jaw, hating himself for continuing but unable to stop. “And yet, I’m smiling. Happy, even. And there’s someone else with me. They’re pulling me up to… somewhere. Somewhere perfect, peaceful. Somewhere I should be—” He stopped, swallowing hard, willing the words to stay down.
“The mirror shows you what you want, Regulus. You’re much too smart to be taking this as face value.” James’ voice was oddly grounding. “It’s terrifying, don’t get me wrong. But this isn’t bad, and the mirror isn’t broken. You’re just looking at it wrong.” James looks vaguely vexed at what he himself was saying.
“Right.” Regulus brought his hand to his furrowed eyebrow, trying to sort through the thoughts racing in his head.
“Talk it through, maybe we can make sense of it.” James’ voice was dangerously encouraging, and if Regulus was a bit more tired, and weaker, he probably would have collapsed in his arms like a maiden in distress,
“Soon.” Regulus settled on instead, gaze still unfocused, facing the direction of the mirror.
“Soon.” James said it like a promise.