Mortal Once More

September 1st, 1982 - Hogwarts Castle

Regulus feels as though he’s barely had a chance to sit down in his new office to process the overwhelming feeling of being back at Hogwarts - not to mention marvel at that Welcome Feast, he’d forgotten how incredible the house elves’ cooking was here at the school - when there’s a sudden knock at his door. 

He experiences a brief moment of alarm - he’s always on edge these days, even here in the castle, it seems - before the door opens without permission, and Lupin pokes his head into the room. 

“Evening, Regulus,” he says, with a somewhat sly grin. “The headmaster told me you had some medication for me?” 

He sighs.

“Yes, I’ve got it here,” he responds, trying to ignore the slight twist of anxiety in his stomach as he gets up. “I suppose you’d better come in, Lupin.” 

“And I’m thrilled to see you too, Regulus,” the scarred man quips as he enters the office, closing the door behind him.

Regulus makes sure the other man sees his disdainful eye roll before turning to take the plain silver hip flask from his desk, full of the potion that he’d spent the last week and a half of August concocting.

“What, you’re just going to make me swig it out of that?” Lupin asks indignantly. “I thought you Blacks were known for being elegant and classy hosts?” 

“Well, we’re not exactly accustomed to hosting half-blood werewolves,” Regulus snarks back at him. 

He’d expected the other man to narrow his eyes at that; but to his slight surprise, Lupin just grins, looking rather delighted by his sarcasm. 

“Touche. But nevertheless, I would prefer to actually see what I’m drinking - especially when it’s a mysterious, complicated potion that I’ve never drunk before in my life.” 

Regulus lets out an exaggerated sigh, casting him a dark look, even as he twirls his wand in midair, silently summoning a silver goblet from the cabinet in the corner of his office and pouring the Wolfsbane potion into it from the flask, until the goblet is full to the brim. 

“Here,” he mutters, handing it to Lupin, who has helped himself to one of the dark green velvet armchairs by the fireplace - whatever flaws Sirius might have rightfully pointed out in Slughorn, Regulus is still thankful that he’d left much of his stylish, comfortable furnishings in his office. “Happy now?” 

Lupin looks down at the silver embossed goblet, a mischievous grin spreading across his face, which Regulus does not find reassuring in the slightest.

“The Black family crest,” he announces, looking up at Regulus. 

“Well, you said you wanted to be hosted in style.”

“So you stole this from Grimmauld Place?” 

“I can’t ‘steal’ things from Grimmauld Place,” Regulus retorts, irritated. “It’s my own house, Lupin, I live there.” 

“Well, yes,” the other man counters, his grin widening, “but did you actually ask your mummy’s permission to take Black family heirlooms with you, while you went off to work for Dumbledore?” 

Regulus stares at him for a moment, speechless, not wanting to admit that Lupin may have scored a hit - although, judging by the insufferably smug grin on the other man’s face, he already knows that. God, he’d forgotten just how annoying his brother’s boyfriend could be. 

“Just drink the damn potion, Lupin.” 

Lupin’s smirk vanishes abruptly as he stares down at the potion in the silver goblet. It’s a deep navy blue, almost black, with curls of blue smoke drifting lazily off the surface; Regulus had charmed the hip flask to ensure it stayed as hot as it was supposed to. Lupin looks more than a little uneasy as he stares down at it, and Regulus realises suddenly that his teasing had been more to procrastinate than anything else.

“So…are you absolutely sure you’ve made this right?” he asks nervously. 

“I’m pretty sure, yes,” Regulus responds with another eye roll - although, if he’s honest, he’s more nervous than he cares to admit. 

The Wolfsbane Potion is by far one of the most complicated potions he’s ever had to make, as Dumbledore had warned him it would be, before he accepted this post. It had taken him a week and a half to brew up, during which time he’d had to constantly check on it, giving it precisely the right amount of counterclockwise stirs and double checking all of the ingredient amounts at least fifty times. In fact, Regulus probably hadn’t needed to check on it quite as often as he had done, but his anxiety over it meant he hadn’t been able to prevent himself. The potion’s shade of navy blue comes from adding precisely the right amount of purple wolfsbane flowers, also known as aconite or monkshood, which is the potion’s core ingredient, but also one of the most dangerous ones he’s ever handled - if he had added even fractionally too much, the potion would become highly toxic, even lethal. Even more anxiety-inducing is the fact that Regulus hasn’t even been able to test the potion himself - it needs exactly the correct amount of wolfsbane in order to be effective for Lupin, but for any person who doesn’t happen to be a werewolf, ingesting less than half the amount that’s required for this potion would be lethal. 

On the other hand, understanding the incredible stakes riding on getting this right, Regulus had been more cautious making this than he’s ever been brewing any other potion in his life; he’s still not absolutely sure that he’s got it exactly how it’s supposed to be, but he’s as certain as he’s ever going to be, he supposes. Making this incredibly stressful potion has also made him realise that it’s small wonder it had taken so long for anyone to develop it. Given that most wizards view werewolves as inherently dangerous and evil, rather than considering lycanthropy as a disease that they suffer from, most wizards would also never bother to even attempt this incredibly difficult and potentially toxic potion to help ease their ailment. 

“But are you sure it’s supposed to be that colour?” Lupin presses, still eyeing the potion in the goblet suspiciously. 

“Yes,” Regulus replies testily. 

“And it’s definitely supposed to be smoking like that?” 

“Lupin,” he says, through gritted teeth, “as far as I recall, one of us was hired as the resident Potions expert, and it was not you. I promise you, I have done everything physically possible to ensure that potion is safe for you to drink. But if you’d rather not risk it, you can feel free to hand it back to me and just mindlessly run amok around Hogwarts on the full moon instead. No skin off my back - I’m just trying to do you a favour here.” 

The other man pales at the very idea of that, as Regulus had known he would. 

“You’re doing it because Dumbledore told you to,” he mutters under his breath, causing Regulus to narrow his eyes warningly at him. “But fine, I take your point.” 

Tentatively, still looking at the navy potion as though it might suddenly jump up and bite him, Lupin raises the goblet to his lips and takes an extremely cautious sip. Immediately, he pulls a face, grimacing violently. 

“Oh god, what’s wrong?” Regulus exclaims, forgetting his cool, authoritative tone instantly as he panics that he’s made it wrong after all, already tensed to run over to his poison antidotes cabinet. “Does it burn, or something? How do you feel?” 

“No, it doesn’t burn,” the other man replies, still grimacing dramatically. “It just tastes disgusting.” 

“Oh for god’s sake,” Regulus huffs, even as he feels lightheaded with relief for a moment. “Dramatic much, Lupin? Clearly you’ve been living with my brother for too long.” 

He grins at that, despite himself, although the ridiculous grimace appears again as soon as he takes another small sip.

“Christ, it tastes like licorice,” he mutters.

“What are you talking about?” Regulus asks, baffled now as he frowns at him. “Licorice tastes nice!”

“Well, looks like Sirius might have been right,” Lupin answers, staring at him in bewildered disgust. “Maybe you are a little bit insane, Regulus.” 

Regulus huffs at him indignantly again as he takes another tiny sip, grimacing again like a child being forced to drink medicine. 

“Can’t I add some sugar to it? Or maybe even melt some chocolate into it?” he adds hopefully. 

“No, Lupin, not unless you want to make the potion completely useless,” Regulus answers, closing his eyes and pinching the bridge of his nose as he prays for patience.

“Fuck.” 

“Look,” he says through gritted teeth, opening his eyes again. “That potion is perfectly safe - but if you don’t shut up and just drink the damn thing, I may kill you myself.” 

Lupin looks at him over the goblet, raising one eyebrow. 

“Well,” he says, sounding almost impressed. “I suppose we’re even with the death threats now.” 

Regulus stares at the other man in shock for a moment; then, without meaning to, he lets out a surprised laugh. 

“Just chug it, for god’s sake,” he tells him, still laughing a little. “It will be over quickly that way.” 

Lupin sighs, pinching his nose and closing his eyes as he gulps the rest of it down. 

“Disgusting,” he complains, shuddering as he hands the empty, still smoking goblet back to Regulus.

“Yes, I think you’ve made your opinion clear by now, Lupin,” Regulus snarks at him, rolling his eyes again. “Dumbledore told you that you have to take it every night for the week preceding the full moon, right?” 

“Fuck,” he mutters again, his eyes widening in horror. “On second thought…maybe I’ll just take the mindless violence.” 

Regulus laughs again, and Lupin grins at him, despite himself. 

“I refuse to believe it’s that bad,” he says, shaking his head as he uses a quick cleaning charm on the goblet, sending it zooming back to join the other silver goblets in the cabinet with a casual flick of his wand. 

“Why don’t you try it for yourself and see?” Lupin asks, narrowing his hazel eyes at him.

“I can’t,” Regulus retorts. “I’m not a werewolf, so that amount of wolfsbane would be lethal for me.” 

“Convenient,” the other man quips dryly. 

Regulus rolls his eyes again. 

“Well, if that’s all you’ll be needing from me, Lupin…” he starts, making to stand up. 

It’s been a long and somewhat overwhelming day - a long week, really, what with the anxiety over that stupid potion - and the thought of settling into a four-poster bed with the familiar, soft sound of the lake lapping gently against the windows sounds gloriously tempting. 

“Oh,” says Lupin, looking more put out than he would have expected. “Are you chucking me out already? I didn’t realise I was that annoying - maybe I have been living with your brother for too long.” 

Regulus frowns at him, perplexed now.

“Didn’t you just come here for your potion?”

“Don’t worry, Regulus, I wasn’t intending to seduce you, if that’s what you’re looking so worried about,” the other man replies, grinning again. “I mean, don’t get me wrong, you’re very pretty - runs in the family, clearly, although don’t tell Sirius I said that - but you’re also a bit of a prick.”

“Oh, like my brother isn’t?” Regulus retorts before he can stop himself.

“Oh, of course he is,” Lupin replies. “In a different way, of course - but I accepted that as part of the package long ago, when I fell in love with him. No offence intended, Regulus, but I think one Black brother is quite enough for me - besides,” he adds, nodding towards the goblets in the cabinet, “Sirius makes me hot chocolate with bourbon, which tastes much better than the shite you just forced on me.” 

Regulus rolls his eyes again, although he can’t help grinning slightly. Lupin grins back at him.

“Look,” he says, sounding much more genuine now, “even though it might not seem like it, I really am grateful for the effort you’ve gone to to make that potion for me. Although it really is foul,” he adds as a side note, as though Regulus might not yet be clear on that point. “And it seems to me that, if the two of us are going to be teaching together here at Hogwarts for at least the next year, we should at least try to get along, right?  I mean, I think I can probably manage to be civil for at least ten minutes without yelling at you or trying to kill you, unlike my idiotic boyfriend.” 

Regulus still feels a little awkward around Lupin, but he can’t deny that the man has a point; it’s not particularly feasible to just avoid each other for the next year. So he sits back down opposite him. 

“Your boyfriend is an idiot,” he mutters. 

“Yes, I’m well aware,” Lupin sighs. “And yet, I’m still head over heels in love with him.” Regulus grimaces a little, and the other man laughs. “Suppose you’re going to tell me that must make me an idiot, too?” 

“Probably, yes,” Regulus replies, deadpan. Lupin just grins again. 

“So, have you got anything else to offer me? Something that doesn’t give me the urge to be sick? You’re supposed to be a gracious and elegant host, remember?” 

With a somewhat exaggerated sigh, Regulus flicks his wand over his shoulder. A moment later, two of the Black family’s silver goblets come soaring out of the cabinet towards them, along with one of the finest French wines from the Grimmauld Place cellar, which Kreacher had tearfully pressed on Regulus just as he’d been leaving, after he’d reassured the elf that he would be fine and did not need to bring an entire year’s supply of food up to Scotland with him. 

“Impressive,” Lupin comments, raising an eyebrow again, as the bottle of wine begins to neatly pour a measure into both goblets. “This is the good shit, I take it?” 

“Yes, Lupin,” Regulus huffs, rolling his eyes at the other man’s crassness. “This is, as you call it, the ‘good shit.’” 

“Excellent,” he grins, picking up the goblet much more enthusiastically this time. He starts to raise it to his lips, but hesitates.

“Incidentally…if you had fucked up that potion, what would happen to me?” 

“Oh for god’s sake, I did not fuck up that potion,” he snipes. “But, if I had, you would very likely die.” Lupin pales a little. “But, if that was the case,” Regulus adds hastily, “you would most likely already be writhing in paroxysms of agony. And you don’t appear to be, you’re just sitting there asking me irritating questions which I’ve already answered, which is how we know that, once again, I did not fuck up the potion.” 

“Alright, alright,” the scarred man replies, looking finally reassured as he raises the hand not holding the goblet in surrender. “Noted. I’ll keep an eye out for any writhing, or agony. Anyway, if you did happen to accidentally kill me, I imagine Sirius would soon return the favour, so we’d be even soon enough.” 

“I’ll try and remember not to, then,” Regulus counters dryly. “No promises, though.”

“Here’s to our continued existence, then,” says Lupin, grinning more broadly than ever as he raises his goblet.

Regulus sighs again, but clinks his goblet against the other man’s, thinking as he drinks that it’s certainly the strangest toast he’s ever partaken in. 

“Feels strange being back here, doesn’t it?” Lupin says, his grin fading a little. “Well, I mean…not here here, I can’t say I ever spent all that much time in Slughorn’s office when I was a student. But you know what I mean.” 

“Yeah,” Regulus replies quietly. “I do know what you mean. It does feel sort of strange. But…it feels right, too. You know?” 

“Yeah. It does,” the other man agrees. “I feel like I might actually be able to help people here, rather than just being sent on missions that make me feel like shit all the time.”

“Think I know the feeling,” says Regulus, with a humourless smile. 

“Hey,” says Lupin brightly, evidently trying to shake the moment of gloom that had settled over both of them as soon as they thought about the headmaster, “did you see Fab’s nephew being Sorted? Little Bill Weasley?” 

Regulus feels his heart skip a beat immediately at the mention of Fabian; he quickly raises his goblet to take another sip of wine, hoping Lupin won’t notice the blush he can feel creeping across his face. 

He’s been trying his best not to think about Fabian Prewett too much, trying not to dwell too much on the expression of disappointment that had flickered across the redhead’s face when Regulus had told him about the job he’d accepted at Hogwarts.

“Oh,” Fabian had said quietly.

“Dumbledore said you were the one who spoke to him about me?” Regulus had asked awkwardly.

“Yeah, I did…well, I didn’t exactly ‘speak to him’,” Fabian had replied, with a sheepish grin. “That makes me sound a hell of a lot politer than I was. I was just getting bloody sick of him putting you on missions that made you miserable all the time. He didn’t mention anything about giving you a job at Hogwarts, though…did he say how long it would be for?” 

“For the next year, at least.” 

“Oh,” Fabian had said again. He had hesitated, a strange look in his eyes for a moment. “So…do you want to leave? To go to Hogwarts, I mean?” he’d asked, the question sounding a little rushed, as though he’d said it without really meaning to.

Regulus had paused at that, staring back at the redhead, not quite sure what Fabian expected - or wanted - him to answer.

“Well…yes. I think so. Sort of a fresh start, you know?” Fabian had nodded awkwardly at that, looking down at the floor. “Why?” Regulus had asked, suddenly feeling a rush of panic and remorse at the idea that he might have upset him. “Do you not want me to go?”

The redhead had looked almost lost for a moment; but then he had met Regulus’s eyes again with a bright smile, albeit one that had looked rather forced. “What? Of course I want you to go, Regulus! You’ll be amazing!”

“I will?” he’d asked, uncertain.

“Of course you will!” Fabian had replied, his grin growing more genuine. “And more importantly, you’re right - it’s a chance to get away from the war, isn’t it? Away from all of the shit that’s been making you feel awful about yourself. And you’ll be much safer at Hogwarts,” he’d added, looking more reassured, as though he was persuading himself. “And hey, you can keep an eye on my nephew, he’s just about to start there! God knows, Molly would love to get regular reports,” he’d said, with a grin and an eye roll. 

“I suppose…” Regulus had answered awkwardly. 

Fabian’s grin had suddenly vanished again, his expression becoming almost…nervous. 

“Can I…would it be alright if I visited you, sometimes? While you’re there?” 

Regulus had stared at him for a moment, speechless. It’s still difficult to believe, sometimes, that he has someone who genuinely cares about him this much, who actually misses him when he’s gone - he hasn’t had any connection like that since he and Sirius were young children, really.

“I’d be a bit annoyed at you if you didn’t,” he had answered truthfully, when he’d remembered how to form words again - and Fabian’s answering grin had seemed bright enough to keep Regulus going for a little while, in his absence. 

They hadn’t actually determined any specific dates for Fabian visiting him at the castle yet, but Regulus has been trying his best not to dwell on it too much. His immense anxiety about brewing the bloody Wolfsbane Potion perfectly had been a useful distraction, at least. He knows he should just be thankful that the other man still wants to be his friend, even after Regulus’s moment of insane recklessness back at the Potters’ cottage in Godric’s Hollow, when Potter had walked in just in time to stop Regulus from doing something stupid that he wouldn’t have been able to take back, that would likely have ruined his closest friendship. And he is thankful that Fabian still wants to be his friend. It won’t do him any good, he reminds himself sternly, for what feels like the hundredth time, to dwell on the expression on the redhead’s face, to run through Fabian’s words over and over in his head, wringing them for hidden meanings, wondering over and over again if he, Regulus, had said what he was supposed to say…

Do you want to leave? 

“Hello?” Lupin says suddenly, bringing Regulus back to the present with a bump. “Earth to Regulus Black?” 

He realises, then, that he’s still waiting for an answer.

“I…what was the question again?” Regulus asks awkwardly, feeling his cheeks burning.

“I asked you if you saw Fab’s nephew Bill being sorted?” the other man asks.

“What…oh, yeah,” he replies hastily, remembering the freckled boy with long hair as vivid a shade of red as his uncle’s, tied back into a ponytail.

“He looked bloody relieved when the Hat shouted Gryffindor, didn’t he?” Lupin remarks. “But then, I’m not surprised; Fab told me Molly might have considered disowning him if he’d been put in any other House,” he sniggers. 

“Mm,” Regulus agrees noncommittally, trying his best to sound neutral, hoping against hope that Lupin can’t tell how flustered he is at just the mention of Fabian Prewett’s name. But judging by the smirk spreading slowly across the other man’s face, it hasn’t escaped his notice. Dammit. 

“I think it will do him good to be here at Hogwarts, though, poor kid,” says Lupin, still grinning a little. “He’ll finally have time to focus on himself, make some friends his own age, instead of feeling like he has to look after five younger brothers and a baby sister all the time. Not to mention, he’s probably been trying to take care of his mum, too, ever since…”

His grin fades as he trails off. Regulus, knowing exactly what he was about to say, feels another twinge of pain and echoed grief on Fabian’s behalf, remembering the haunted, lost expression on his face that night.

“Sirius went to Diagon Alley with Bill, Fab and Arthur to get Bill’s school books, you know,” Lupin says quickly, in a transparent attempt to change the topic. “Bill was so excited to finally be getting his Hogwarts stuff, Sirius said it was pretty sweet. Although bumping into Malfoy in Flourish and Blotts wasn’t quite so enjoyable, apparently.”

“What?” Regulus asks, finally distracted from his thoughts of Fabian. “Malfoy was hanging around? In Flourish and Blotts?” 

“Yep, according to Sirius,” Lupin replies, taking another sip of wine. “Apparently he made a beeline for them, started in with his usual shit about blood traitors, and asked Arthur what was the point of being a disgrace to the name of wizards if ‘they didn’t even pay him well for it.’ Arthur didn’t retaliate to any of it - he’s used to it, I suppose - but then when Malfoy started in on Bill, picking up the school books he’d just got, without the kid’s permission, and sneering something about ‘tatty second hand books’, Arthur snapped.”

“Snapped?” Regulus echoes. 

“He punched Malfoy in the face, right in the middle of the bookshop,” Lupin clarifies, his grin widening, and Regulus lets out a startled laugh. 

He can’t imagine that Narcissa will be especially thrilled when she hears - but then, although his cousin has always been kind to him, it still has to be said that her taste in men is pretty dire. 

“What, he didn’t even throw a curse at him?” he asks, grinning a little himself, even though he knows it’s childish. “He just went straight to Muggle duelling?” 

“Well, Arthur is pretty fond of Muggles,” Lupin responds with a shrug, grinning even more at the amused look on Regulus’s face. “Anyway, it’s quicker than drawing your wand, isn’t it? I don’t blame Arthur, either; I mean, it’s one thing for Malfoy to be a dick to him, but taunting his kid? Bill was really excited about the Diagon Alley trip, apparently, but then he was incredibly upset and anxious after the Malfoy incident. No wonder; I’m sure the poor kid has never been targeted and publicly bullied by an adult he doesn’t even know.” 

“Lucius has always been like that,” Regulus sighs. “He likes to pick on people smaller than him.” 

“Yeah, I remember,” Lupin replies. “Probably why Snivellus used to follow him around all the time; trying to get on his good side before he became one of those smaller people.” 

That makes Regulus pause for a second; Snape had often tried to ingratiate himself with him, too, despite being in the year above. But Regulus had never been able to stomach him for very long; the greasy boy’s desperation to pretend he was a pureblood had set his teeth on edge. Not to mention, the way he had constantly spewed vitriol about Sirius had always made fury bubble in the pit of Regulus’s stomach, no matter how hard he tried to hide it. 

“So what happened, then?” he asks, hastily trying to change the subject. “After Arthur Weasley punched Malfoy?” 

“Well, Fab and Sirius both tried to follow his example, it seems,” Lupin answers, rolling his eyes, even as he’s still grinning, “but the Flourish and Blotts staff came over and broke it up before they could manage it. They nearly got thrown out, except Malfoy left of his own accord. I don’t think he’d expected to have his pride quite so dented when he’d walked in; apparently Arthur gave him a black eye. According to Sirius, when the shop assistant came to break them up, Malfoy shoved Bill’s school books back at him and snarled, ‘Take them, boy, they’re the best your father can afford for you’, and then he turned and stalked out of the bookshop without another word. Sirius says he just wishes he’d had a chance to punch the bastard first.” 

“Of course he does,” Regulus sighs, rolling his eyes. “But - I assume someone followed him to check where Malfoy was heading? He went to Knockturn Alley, presumably?” 

“Yeah, Sirius followed him out,” the other man answers, “though, knowing him, probably more because he still wanted to get a punch in, rather than because he wanted to gather any actual intelligence for the Order,” he adds, rolling his own eyes affectionately. “But apparently, Malfoy just Disapparated immediately.” 

“He might have already done something on the Dark Lord’s orders before going to Flourish and Blotts, though,” Regulus replies, frowning. He doesn't remember hearing anything about Lucius having been given a mission to Diagon Alley recently. “I’m assuming somebody made a report to Dumbledore?” 

“Yeah, of course, Fab did,” Lupin responds. “But they couldn’t find any evidence that Malfoy had gone anywhere else that day, in Knockturn or Diagon.” 

“What, so Malfoy just went to Diagon Alley for the sole purpose of being a colossal dickhead to Arthur Weasley and his eleven-year-old son in Flourish and Blotts, and then Disapparated?” Regulus asks sceptically, raising an eyebrow. 

Lupin shrugs.

“Looks like it. I mean, I wouldn’t put it past him, would you?” 

“I suppose not,” Regulus mutters, though he’s talking more to himself than Lupin now, thinking hard. 

Yes, Lucius Malfoy certainly is a nasty piece of work, but it still doesn’t seem entirely characteristic for his cousin’s husband to go out of his way like that, for the sole purpose of finding somebody to upset. It’s not like he would have any need to be in Flourish and Blotts; as far as Regulus remembers, the Malfoys’ son is still a toddler, about the same age as the Potters’. So definitely not old enough to be needing school books yet. And the sort of reading material that would catch his interest would more likely be found in Knockturn Alley’s various bookshops devoted to the Dark Arts, where Malfoy would be far less likely to bump into the sort of people he considers far beneath him. Regulus knows for a fact that Lucius Malfoy is self-serving through and through; he won’t usually do anything unless he can see what benefit there is for him. 

So what was he doing in Flourish and Blotts? 

“Ah, you’ve gone quiet again,” Lupin sighs, startling Regulus a little as he sets his goblet down. “Fine, message received - I’ll piss off and leave you in peace for the rest of the evening, shall I?”

“Oh, I didn’t mean…” Regulus begins awkwardly. “Although, actually, now you mention it…”

Lupin laughs. 

“Don’t worry, Regulus, I’m not offended, I promise,” he reassures him with a grin, stretching his gangly limbs as he stands. “I’m sort of exhausted too, actually. Long day. Thank you again for the potion - even though it is utterly vile. The wine was a bit nicer, though.” 

Regulus rolls his eyes again. 

“You’re welcome, Lupin. I look forward to hearing more of your whingeing when you come back tomorrow for your second dose. You have to keep taking it through the whole week, remember?”

“Ugh,” the scarred man replies, grimacing dramatically again, and Regulus laughs. “Oh, and Regulus?”

“Yes?”

“If we’re going to actually make an effort to be friends this year, or friendly at least - do you think maybe you could stop calling me ‘Lupin’ all the time? It just feels weirdly formal. Or like you can’t stand me. And we’re not really aiming for either of those, are we? Just plain ‘Remus’ will be fine.”

“Oh.” Regulus blinks, surprised. “Alright. Goodnight then. Remus.”

It feels strange. 

“Much better,” says Lupin - Remus -grinning at him again. “You don’t have to look so agonised, you’ll get used to it soon enough.” His grin takes on a wicked edge. “So can I call you ‘Reg’ now? Sirius does.” 

Regulus narrows his eyes at him.

“Don’t push your luck, Lupin.”

He laughs. 

Remus continues to grimace and make faces every time he takes another dose of the Wolfsbane Potion, but they find to their immense relief that not only does the potion not poison him, it works perfectly. The transformation itself is still agonising, apparently, not even Wolfsbane can change that - although Remus has experienced the pain so often that he practically shrugs it off - but, for the first time in his life, he spends the night of the full moon curled up quietly on a chair in his office, without howling, without shrieking or trying to bite or claw at himself, retaining his human mind and instincts even in the form of a wolf. 

According to Remus, it’s rather a strange and unsettling feeling to be in the body of a wolf while still thinking human thoughts - apparently, he’s so used to transforming and fully losing his human consciousness every month that it’s become a release in some ways. Regulus thinks he can actually understand that, when Remus confides in him - it would certainly be a relief to escape from his own mind every now and then. 

But nevertheless, the other man is still thankful to Regulus for ensuring he can be at Hogwarts without endangering anyone around him, or having to be smuggled into the Shrieking Shack like before. He certainly seems happier - in fact, Regulus is fairly sure he’s never seen Remus this happy before. 

Regulus had never really considered the reasoning behind Dumbledore’s hiring Remus for the post of Defence Against the Dark Arts teacher, despite the added complications of brewing the Wolfsbane Potion for him monthly - he had sort of assumed it was just the most convenient solution for the headmaster, after Sirius had demanded Dumbledore stop sending him on dangerous undercover missions with the werewolves. 

But, to Regulus’s slight surprise, it seems that Remus Lupin is absolutely in his element as a Hogwarts teacher. His brother’s boyfriend has always struck him as quiet, introverted, private - although perhaps that’s mostly just in contrast to Sirius - even if he is capable of temporarily incapacitating someone with one expertly timed sarcastic quip. Nevertheless, it quickly becomes apparent that the students at Hogwarts, for the most part, adore their mysterious, quietly mischievous new Defence Against the Dark Arts teacher. 

Perhaps Regulus shouldn’t be surprised. Lupin - Remus, he reminds himself again - has an inherent love of learning, and he loves passing the things that he learns onto other people. As far as Regulus can see, he’s kind, patient and encouraging with every single student that he teaches, somehow seeming to learn all their names within minutes, reassuring them when they come to him about their worries and cheering them on when they confide in him about their hopes and achievements. He has a particular knack for lifting up and encouraging those students who feel small, who are particularly anxious or unsure of themselves. Fabian’s nephew Bill Weasley, for instance, is quiet, shy and nervous, frequently seeming to walk around in a kind of frightened daze, evidently finding it difficult to settle in at Hogwarts. Regulus rarely ever sees the boy looking at ease, unless he’s talking to Remus, who reassures him and makes him laugh. On more than one occasion, in fact, Regulus has walked past Remus’s office to find a veritable queue of students waiting for him; when he’d assured them that Professor Lupin would just accept their overdue work in his next lesson, they had told him they were ‘just there for a chat.’ Regulus really isn’t quite sure how he does it. Perhaps it’s something to do with the emergency stash of chocolate in his office, theoretically reserved only for students in need of comfort, although Regulus knows firsthand that Remus isn’t averse to snapping off a few pieces for just the two of them, when they’ve retired for wine night after student curfew. 

Never having known much about Remus Lupin outside of the context of being Sirius’s best friend and later boyfriend, there are many things about him that it turns out Regulus had forgotten, or perhaps just never fully appreciated. He had forgotten, for instance, that the other man used to run an informal study group for other students, when he was a student himself; people from every house except Slytherin had flocked to him, claiming he ‘explained things better than anyone else’. Now he thinks about it, in fact, Regulus is sure he remembers hearing Sirius and Potter teasingly calling him ‘Professor Lupin’ on more than one occasion, back in those simpler days - though he had also seen Remus casually flip the two of them off in response. 

And, perhaps due to all the tension and baggage that he and Sirius carry between them, Regulus had never quite realised until they got to Hogwarts how funny Remus Lupin could be. He’s more private and introverted than both Sirius and Potter, it’s true, but he still has a subtle, quiet sense of mischief that Regulus has been catching glimpses of  - in the way that he deals with Argus Filch bothering students, for instance - and a quick, dry wit that makes sparring with him rather entertaining. It’s rare for Regulus to find someone who can match his own sarcasm. 

On top of this, Remus is perceptive - annoyingly so, on occasion - and, now that he believes Regulus is trustworthy, far less judgemental than he had seemed when Regulus had first met him. The suffering he has endured through his many transformations, as well as the spying duties among the werewolves that he’d been ordered to undertake, have ensured that he doesn’t see the world, or the war, in stark black and white tones. He doesn’t assume, like Sirius does, that everything must be either wholly good, or wholly evil. When Regulus tries to explain some of the immense guilt he feels about the information he’d been forced to pass to the Dark Lord, on Dumbledore’s orders, Remus explains in turn the sympathy he can’t help but feel for some of the other werewolves, even the ones tempted by Greyback’s promises. 

“They’ve been shunned by the rest of wizard society, they face stigma and harsh restrictions from the Ministry wherever they go, no matter what they do, over something they can’t bloody control, that causes them fucking agony once a month,” he tells Regulus. “And most of them aren’t as lucky as I’ve been; they’ve been thrown out with nowhere to go, and they certainly haven’t had friends who not only stuck by them, but risked their lives to become Animagi for their sakes. Honestly, it’s not much wonder they’re tempted by Greyback’s offer of protection and power, is it? It’s not like the Ministry is offering them better options. They’re alone, lots of them. I’ve managed to persuade a few of them away from Greyback, away from Voldemort, but…it’s barely more than a handful. I kept trying, but still so many of them slipped through the cracks. It was bloody exhausting, sometimes I thought it would kill me. And even now, when I know that so many of the ones I tried to convince have fully joined Greyback, when I hear about new attacks…there’s still a part of me that wonders what more I could have done, a part of me that desperately wishes I could help them, the way my friends helped me. But…” he sighs. “I can’t explain that to Sirius, can I?” 

“No,” Regulus answers gently. “You probably can’t.”

Remus leans back in his chair.

“All of those bloody missions were putting a huge strain on our relationship, you know,” he says conversationally. Regulus blinks, somewhat surprised Remus is confiding in him like this. “Even after Sirius apologised for believing Peter’s lies about me.” His mouth twists, pain flickering in his hazel eyes at the memory, and Regulus realises afresh just how much that must have hurt him. “He’s promised never to doubt me again, after that, and I believe him. But still…he wanted me to stop going on those missions, because he could see how much it was hurting me every time I failed. But I was reluctant to give up on anyone if there was the slightest chance I might help them, even though I knew it would kill me eventually if I kept trying and failing, and hating myself for it every time. Sirius could never quite see why I would want to keep risking my own life and sanity for people who were so tempted by power and darkness. Kept telling me it wasn’t my responsibility to feel guilty for failing them, even when I reminded him he never used to listen when I told him the same thing…”

“What?” Regulus asks, bewildered for a moment. “Why would Sirius have felt…?” 

He can see clearly, from the guilty expression on the other man’s face, that Remus had accidentally let something slip, something that his boyfriend wouldn’t have wanted him to say. 

Oh. Sirius used to berate himself over failing him? Regulus doesn’t quite know what to do with that knowledge, how to feel. Especially as he’s spent so many years hating himself for failing Sirius…

“Anyway, the point is,” Remus says hastily, “Sirius trusts me again, he knows I’m never going to join that side, but he still doesn’t quite…understand me, you know? Not completely, anyway. Even though he’s tried harder for me than anybody else ever has. You know?” 

“Yeah,” Regulus responds quietly. “I think I do.”

They’re both quiet for a moment, lost in their own thoughts. 

“I love your brother so much, and I miss him like crazy sometimes,” Remus murmurs, staring into the fireplace absentmindedly as he speaks. “But at the same time, I feel so lucky to be back at Hogwarts. I feel like I can actually help people now, like I’m actually making a difference in the students’ lives; maybe I might even manage to improve their chances, once they’re out in the real world, faced with the realities of the war. You and me, Regulus…we’re both better off here at the school, aren’t we?” 

Regulus stares at him for a moment, lost in thought. He’s not sure it’s quite as simple as that, for him. 

It’s true that Hogwarts feels more like home for him than Grimmauld Place ever has. He can hardly claim to have very many ‘happy’ memories, but the castle certainly holds some of his best, and being back here brings them rushing back. Regulus wishes he could just pretend, being here, that he’s gone back to a simpler time, back to a time before Sirius had detached himself, to a time when the talk of ‘war’ and ‘choosing sides’ was nothing but whispers, rumours which nobody fully believed would develop into anything more substantial or threatening. 

But it’s impossible to pretend that he’s truly gone back in time; Hogwarts isn’t that isolated from the outside world. 

There are new disappearances and deaths reported in The Daily Prophet almost every day, and although Regulus knows that he hasn’t destroyed these lives at least, it doesn’t absolve him of the twisting guilt that the printed names evoke, reminding him all over again of those deaths that he did have a hand in. Besides which, it’s another reminder that the war is still raging on outside the castle’s walls, seemingly endless. He himself might be happier here at Hogwarts, but that doesn’t change the fact that the Order is still only managing to fight the Death Eaters to a stalemate, and barely even that. 

It’s also rather difficult to ignore the reality of the war when Regulus is still having to write to the Dark Lord every week or so, reporting on the movements of Dumbledore and those staff members most loyal to him, constantly meeting with the headmaster still to determine how much it is safe to pass on, how much misinformation he can give without suspicion falling on him. Of course, he is already having to deal with plenty of suspicion from the teachers who are now his colleagues. McGonagall, Flitwick, Sprout and Hagrid don’t know him as well as Dumbledore and Remus do, but they all remember him as a student; McGonagall and Hagrid in particular are scarcely bothering to hide their distrust, their amazement that the headmaster has allowed him back into Hogwarts.

Then there’s the fact that Remus has had to bring the still-intact Horcrux with him to Hogwarts, for fear that if he left it in the flat he shares with Sirius, Crouch’s Aurors might come searching without warning at any moment. Thankfully, Remus has it tucked away in his office, so at least they’re not having to pass it back and forth between them any more, and it’s protected by all the spells and defensive magic they, along with Dumbledore, have been able to throw at it; Regulus supposes that, if they have to keep the locket hidden, there’s no safer place for it than Hogwarts. But still, every time he catches a glimpse of the bloody thing, it feels like another reminder of how far they have to go before they can even begin to gain the upper hand in this never-ending war. 

But Regulus knows that he’ll go slowly insane if he just keeps dwelling on all of the terrible things, most of which he’s powerless to change at the moment. So, instead, he’s been trying his best to focus on the things he’s grateful for, the ways in which being back at Hogwarts has changed his life for the better. 

Despite everything, he does feel strangely at home here, where everything is so familiar. He sleeps in the room adjoining his office, next to the Slytherin common room - he had forgotten just how soothing it is in that part of the castle, with the cool green light, being lulled to sleep by the soft lapping of the lake against the windows, occasionally hearing the unearthly, mournful yet beautiful music of the merpeople as they drift past. It still feels strange to see the four house tables from a seat at the teachers’ table; but, to his slight surprise, Regulus has been finding that he does actually enjoy teaching the students here. 

He certainly wouldn’t claim to be as natural a teacher as Remus is; neither kindness nor patience are traits that come particularly easily to him, as he didn’t experience much of either when he was growing up. But just because he didn’t experience those things, he realises, that’s no reason that these students shouldn’t - they’re fresh-faced, hopeful, not yet irreparably damaged or broken by hatred, prejudice or war. Regulus remembers all too well how his own parents had always made him feel small and frightened whenever they thought he wasn’t working or learning fast enough, or putting in enough effort, how they had threatened and punished both he and Sirius if they didn’t study, or if they broke any rules - and then, once it became clear that his brother was a lost cause, they had put even more pressure on him never to waver for a second, never to put one toe out of line, or to speak when he hadn’t been spoken to. Remembering how he had so often been terrified of the adults in his life makes Regulus all the more determined to be quietly encouraging with his own students, to be open and considerate with them. And no, it doesn’t always come easily to him, remembering to be kind, to be patient and understanding when a student makes a mistake - but he’s teaching himself as much as he’s teaching them. He’s watching Remus, learning from him too. He’s not as popular amongst the students as Remus is, he knows that. The Slytherin students mostly seem to like him; in fact, some of the oldest ones sometimes look at him with something that seems to be bordering on awe, which makes him immensely uncomfortable - he can’t help but wonder how many of them have been brainwashed by their parents in the same way he was, whether there are a few that he’s already too late to save. On the other hand, Regulus has noticed other students, on more than one occasion, clearly muttering darkly about him as he passes them in the corridors, giving him a wide berth - especially some of the Muggle-borns. Especially those Muggle-born students who are old enough to remember what he was like as a student. Every time he notices it, his stomach clenches and twists with that far-too-familiar sense of guilt and shame; he knows that those kids have every right to be wary of him, and that makes it so much harder to deal with. 

He does his best to ignore it and press on, knowing that he can’t afford to let the self-loathing cripple him, that there are more important things. 

Because, at the end of the day, Remus is right; this is his chance to actually help people, to change their lives for the better, to make sure these students know what he didn’t know when he was their age - that they have opportunities ahead of them, choices. 

“Regulus?” says Remus’s voice gently, pulling him back to the present again. He jumps slightly. “Lost you again, there.”

“Sorry, I…” he shakes his head a little. “Yes. You’re right. We are better off here at Hogwarts.”

“Of course I’m right,” Remus answers, grinning at him. 

Regulus just rolls his eyes at him, though without any real irritation; he’s used to  the other man by now.

“You, uh, haven’t heard anything from Fabian lately, have you?” Remus asks casually. 

Regulus immediately feels his face heating up, and curses himself as Remus’s grin turns into more of a smirk. 

“Yes, I have, actually,” he says, jutting his chin out and desperately trying to look unaffected. “Why?” 

“I was just wondering,” the other man replies in an innocent tone. “So, he’s sorted out what date he’s coming up to Hogsmeade to visit, then?” 

“Yes, he has,” Regulus answers shortly, already wondering how to shut this conversation down, and whether he and Remus have yet reached a point where Regulus can just flatly tell him to piss off. 

“He wouldn’t be coming up on Halloween, by any chance, would he?” Remus asks, still in that tone of faux innocence. 

Regulus stares at him, caught off guard for a moment.

“How the hell…since when do you know Legilimency? Or have you been going through my letters?”

“Neither, idiot,” Remus sniggers, “and honestly, I’m offended that you think I’d stoop so low. You’re not that interesting, you know, Regulus.” He huffs, and the other man’s smirk broadens. “Sirius told me. They’re both coming up together.” 

“...Oh.” 

He’s not sure how to feel about that. He hasn’t actually spoken to his brother properly, since their argument in Godric’s Hollow. 

“Fabian didn’t mention anything about Sirius coming with him,” he says, feeling faintly annoyed, his eager anticipation now mingling with unease.

“Maybe he was worried you’d just lock yourself away in your office the whole time, if you knew he was bringing your brother,” Remus sniggers. Regulus narrows his eyes at him, which doesn’t seem to faze the other man one bit. “Sirius thought Halloween would be a good time to visit, because we can go out for drinks that night, and then a few days later we can celebrate his birthday in Hogsmeade too - ‘just like the old days, Moony!’” he says, rolling his eyes affectionately as he pulls off an uncanny imitation of Regulus’s brother. 

“Oh. Right,” he says again, feeling more than a little awkward now. He’s not even sure whether he’d be welcome at Sirius’s birthday celebration; he doesn’t remember the last time they’d celebrated together. Remus and Fabian will both be invited, obviously - will Sirius give in and let him come too? He wouldn’t put it past his brother to tell him he doesn’t have an invite - then again, he has a feeling Fabian might have something to say about it, if Sirius tried that. 

“You must be looking forward to seeing my brother, then?” Regulus asks, hoping the other man can’t tell how stupidly anxious he is at this news. 

“Oh, I am,” Remus answers, a ridiculous soft smile lighting up his face for a moment. But then, almost immediately, the smirk is back. “Almost as much as you’re looking forward to seeing Fab, I imagine.” 

Regulus feels his face burning again. Fuck. 

“I…shut up,” he stammers, quickly getting up and turning his back on him.

Remus just sniggers. 

October 31st, 1982

As soon as the Hogwarts ghosts vanish through the walls of the Great Hall, having just finished their annual formation gliding spectacle, applause breaks out, swiftly followed by chatter and gasps of delight from the students as the last of the main course dishes vanish, replaced with pumpkin pasties, pumpkin tarts, toffee apples with eerie little faces carved into them, apple cakes, and huge brightly coloured lollipops and fudges from Honeydukes. The Great Hall is lit up by hundreds of grinning jack-o-lanterns hanging from the ceiling that appears to open onto the stormy heavens, and what with the excited talking and laughter from the students, and the chittering sounds from the cloud of live bats swooping around the place, Regulus can hardly even hear himself speak when he leans over to Remus, sitting next to him. 

“Come on,” he practically shouts into his ear. “Feast is almost finished, the kids will be heading up to their dorms soon - we’re meant to be meeting the other two out by the gates at nine, remember?” 

Remus looks at him with wide, pleading eyes.

“What?” Regulus asks, frowning. “Thought you were excited to see my brother, for some unfathomable reason?” 

“Yeah, I am,” the other man replies indignantly. “But…” he gestures towards the innumerable dishes cluttering the table in front of them. “Food!”

Regulus rolls his eyes - for somebody so lanky, it’s honestly incredible how much food Remus Lupin is capable of putting away. 

“We can get food at the Three Broomsticks!” Remus still looks a little reluctant. “Oh, for god’s sake,” he huffs, “just wrap some up and take it with you, then!”

He looks much happier at that, quickly reaching out to grab a piece of Honeydukes chocolate the size of a small boulder. 

“You’re really going to get through all that?” Regulus asks him sceptically. 

“I’m going to share it with Sirius!” Remus claims, in a thoroughly unconvincing tone. “Because I’m a fantastic boyfriend. Obviously.”

“Obviously. Now hurry up.” 

“Fine, fine, I’m coming,” the other man huffs, clambering to his feet in a somewhat undignified way - though Regulus supposes it’s hard to be dignified when your limbs are that long and gangly. “Wouldn’t dream of keeping you waiting - I know you’re very keen to see our visitors. Well…one of them, anyway.”

“Shut up, Lupin,” Regulus growls, his face immediately burning again. His stomach does happen to be doing excited somersaults - but he’d rather Remus didn’t bloody know that. He attempts to stride haughtily ahead of him out of the hall.  It doesn’t work, of course - Remus catches up to him quickly, still smirking in a very satisfied way, though Regulus isn't sure whether that’s because he’d provoked him so easily, or because he has his chocolate. 

“Well, if you want to get there in time, better move faster than that, Regulus,” he grins, striding easily ahead with his long legs.

“Show off,” Regulus mutters. 

“Oh, shit…” says Remus suddenly.

“What?”

“I just remembered, I have a present for Sirius - it’s in my office, I meant to wrap it properly earlier, I didn’t get a chance…”

“You soppy git, Lupin,” Regulus teases, hoping to get his own back for once - but Remus just shrugs, unfazed. 

“You go ahead and meet them, tell them I’ll just be a few minutes -”

“No,” says Regulus, feeling suddenly alarmed. He’s not sure he’s emotionally prepared to be left alone with Sirius and Fabian, with no buffer. “It’s fine, I’ll just come up with you - might be able to hurry you up a bit.” 

Remus rolls his eyes, but makes no other answer, hurrying immediately up the staircase.

“Remus, wait,” Regulus huffs, following after him. 

The other man is already quite far ahead, and Regulus, panting slightly, follows the sound of his footsteps.

But then, as he turns into the first corridor at the top of the staircase, he hears a strange splashing sound, and Remus’s footsteps suddenly stop. 

“For god’s sake, I said wait…”

He stops, seeing that Remus has come to a halt in the middle of the corridor for some reason, staring at the floor beneath his feet. It takes a moment for Regulus to register that he can see his own reflection staring back at him - the entire corridor is flooded with water.

“What the…? Remus, did you…?”

“Oh my god,” Remus whispers, his voice suddenly hoarse.

“What?” Regulus demands, frustrated at the delay. “Remus, we’re going to be…oh.” 

He stops dead, his breath seeming to freeze solid in his chest as he sees what the other man is looking at.

There’s something strange, hanging from the wall, suspended from a torch bracket. As he edges closer, he realises that the bizarre creature is the crusty old caretaker’s tabby cat - glassy-eyed and stiff as a board. 

And then, as he hears the noise of a chattering crowd of students beginning to make their way up from the Great Hall, Regulus feels an icy thrill of horror as he registers that there are words daubed on the wall beneath Filch’s cat, foot-high words, glistening in the flickering torchlight, written in something that looks suspiciously like blood. 

THE CHAMBER OF SECRETS HAS BEEN OPENED, the message on the wall announces. ENEMIES OF THE HEIR, BEWARE.