Chapter Text
No one had ever suspected that Remus Lupin — sweet, quiet, reasonable Remus — was capable of such violence.
He had them all fooled.
James, Sirius, Peter — Dumbledore .
The day it all unraveled was the day Regulus Black stood up in the middle of a Death Eater meeting and said, "I'm done."
The words were still hanging in the air when Remus’ wand was in his hand , not pointed at Regulus — but at everyone else .
"You heard him," Remus said softly, dangerously, voice calm like still water before a storm. "He's done. And so am I."
There was a pause , as if no one knew whether to laugh or hex him.
But then Rodolphus Lestrange sneered. "Oh, are you, Lupin? And what are you going to do about it, little wolf?"
The smirk on Remus’ face was something none of them had ever seen.
"Kill you."
And he did. Remus Lupin killed Rodolphus Lestrange in less than ten seconds.
No hesitation. No mercy.
Regulus just stood there, wide-eyed but unreadable, as if he knew this was coming — or maybe hoped for it.
Because what no one knew was that Remus Lupin had been marked for nearly two years, and not because he believed in Voldemort — because Regulus had asked him to .
Because Regulus was the only thing keeping him from tearing the world apart.
———
When Remus and Regulus turned up at Grimmauld Place, filthy and bloodied, Sirius stared at them like they were ghosts.
"You—" Sirius started, but words died in his throat.
"Yeah," Remus said, like it was nothing. "Turns out I’m not as soft as you thought."
James stood behind Sirius, pale. "You’ve been working for him ? All this time?"
Remus tilted his head, eyes cold. "Not for him. For Regulus ."
Regulus, quiet beside him, didn’t deny it.
"You would’ve killed us," James said, horrified.
"If Regulus told me to, yes."
Sirius looked like he'd been slapped. "You’re insane."
Remus smiled slightly. "Aren’t we all?"
———
It took Dumbledore himself to intervene, stepping between them, eyes sharp and calculating.
"You will come back to the Order," Dumbledore said.
Regulus raised a brow. "And if I don’t?"
Remus' hand twitched on his wand. "Then we don’t."
Dumbledore studied them. "You would fight your friends, your family, for him?"
"I would fight everyone for him," Remus said without blinking. "I would burn this castle to the ground if he asked me to."
The silence that followed was heavy, but Dumbledore only nodded. "Then perhaps it is best you are both on our side."
———
Back at Order meetings, everyone watches Remus with new eyes .
Sirius keeps a protective hand on his wand. James looks at Remus like he doesn’t recognize him.
And Remus doesn’t care. He hovers near Regulus like a shadow, always watching, always close enough to protect.
When Regulus gets so much as bumped into by an Order member, Remus is snarling like a wolf , eyes flashing.
"You touch him again, and I’ll break your hand," Remus says quietly to Mundungus, who had only nudged Regulus by accident.
Regulus rolls his eyes but doesn’t stop him.
"You're mad," Sirius says one night, staring at Remus across the room.
Remus gives him a sharp smile. "Only for him."
And Regulus?
Regulus just looks at Remus like he’s the only person in the world who ever chose him.
Because maybe he is.
———
Optional Ending (Softer if wanted):
One night, when Regulus is half-asleep in Grimmauld Place, Remus sits beside him, tracing circles on his arm.
"Do you ever regret it?" Regulus murmurs.
Remus looks down at him, eyes dark but soft. "No. Never. You’re the only thing I’ve ever done right."
Regulus leans into him, exhaling.
"I don’t deserve you."
Remus kisses his temple. "You don’t. But you’ve got me anyway."
And in that moment, in that quiet space where no one else exists — they’re all the other has left.
And that’s enough.
Chapter Text
The door to Grimmauld Place slams behind them, and Regulus barely gets his coat off before Remus shoves him up against the wall , growling low in his throat like something wild.
"You’re reckless," Remus mutters, voice a dangerous rasp against Regulus’ ear. "Letting them speak to you like that."
Regulus smirks, tilting his head even though his breath hitches. "You gonna do something about it, wolf?"
Remus' hand is around his throat in a flash — possessive, tight, but careful , like he knows exactly how much force to use. "You shouldn’t provoke me."
Regulus' laugh is soft, dark. "Maybe I want to."
Remus' grip tightens, thumb pressing against his pulse. "You don’t even know what you’re asking for."
"I think I do."
Remus grins, sharp and dangerous, before slamming their mouths together in a bruising kiss , all teeth and tongue, a warning and a promise.
"Mine," Remus breathes against his lips, hands sliding down to grip Regulus’ waist bruisingly. "Say it."
Regulus smirks against his mouth. "Make me."
And oh, Remus will .
✧ Order Meeting Scene — Remus SNAPS ✧
It was supposed to be a simple meeting.
Sit around the table. Talk about the war. Plan.
But when Marlene — of all people — snorted and muttered under her breath, "Death Eaters like him don't change," while looking right at Regulus , something in Remus just snapped .
There was a sharp crack as Remus' fist slammed into the table, rattling cups and startling even McGonagall.
"Say that again," Remus growled, his voice low, dangerous — like something feral barely being contained.
Marlene blinked, taken aback. "What? I’m just saying—"
"I heard you." Remus stood slowly, rolling his neck like he was holding himself back from something violent. "Say it again. About him ."
Regulus’ eyes went wide, whispering, "Remus, don’t."
But Remus didn’t even look at him. His eyes — dark and sharp like a predator — were locked on Marlene.
"You think I’ll let you speak about him like that?" Remus said, stepping around the table slowly, voice soft but venomous. "After everything he's done — everything we've done?"
"Remus, sit down," James said, trying to keep calm.
"Sit down?" Remus laughed, but there was no humor. "I spent years bleeding for this cause, and I’ll be damned if anyone thinks they can breathe wrong in his direction."
Marlene scoffed. "So you're what? His attack dog now?"
Remus stopped, just in front of her. "No." His lips curled into a smirk. "I'm his wolf . And I don’t give second warnings."
The room was dead silent.
Even Sirius was staring, horrified .
"Remus—"
But Regulus grabbed his arm, pulling him back. "Enough."
Remus let out a heavy breath, but didn’t take his eyes off Marlene. "Watch your mouth," he said, voice like steel. "Because next time, I won’t stop."
✧ How They Deal with It After (Angst/Soft Angst + Protective Remus) ✧
Later that night, Remus sat on Regulus’ bed, head in his hands.
"I’m sorry," Remus muttered, fingers tangled in his own hair. "I lost it."
Regulus sat beside him quietly, watching him.
"I can’t— I can’t let them speak about you like that," Remus whispered. "You're mine, Reg. You’ve always been mine."
Regulus leaned over, pressing a soft kiss to Remus’ temple. "I know."
Remus looked up, eyes tired and dangerous all at once . "You’ll tell me if anyone else does, right?"
Regulus smirked faintly. "If I can’t handle it myself."
Remus exhaled, pulling him into his lap, arms locked tight around Reg’s waist. "I’ll always handle it."
Regulus leaned down, brushing their foreheads together. "You're terrifying, you know that?"
Remus chuckled darkly, kissing him slow and deep. "Only for you."
Chapter Text
The door had barely clicked shut behind them when Remus was on him , slamming Regulus against the wall so hard the frame rattled.
"Remus—" Regulus gasped, but it was cut off by Remus’ mouth crashing into his, teeth and tongue and desperate groans .
Remus pulled back only to growl against his throat, dragging his teeth along pale skin , biting down hard enough to leave marks.
"You think I’ll let them talk about you like that?" Remus rasped, his voice low, dangerous, almost unrecognizable. "You think I'll let anyone look at you like that?"
Regulus shuddered in his grip, both turned on and stunned by the sheer force of him. "Remus, it’s fine—"
"It’s not fine." Remus’ hands gripped his hips bruisingly. "You don’t understand, Reg. I’ve bled for you. Killed for you." His lips brushed Regulus’ ear, voice dropping to a whisper. "You belong to me."
Regulus smirked faintly, ever the one to push. "So prove it, wolf."
Something snapped in Remus then — something wild and feral.
"You want me to prove it?" he growled, spinning Regulus around and pressing him into the wall, chest to his back , one hand gripping both of Reg’s wrists above his head, the other sliding down his chest, under his shirt, fingertips dragging possessively along his ribs .
"Remus—"
"Quiet," Remus hissed in his ear. "You’re mine. Say it."
Regulus shivered, arching back into him, but stayed silent, lips curling in a smirk.
Remus’ hand slammed his wrists harder against the wall. "I said say it."
Regulus gasped, head falling back against Remus’ shoulder. "I’m yours."
Remus groaned deep , grinding against him, already hard and desperate. "That’s right. You think anyone else can have you? Think I’ll let anyone else touch you?"
Regulus smirked. "Maybe I want them to try."
Remus snarled, spinning him back around and lifting him up , making Regulus wrap his legs around his waist as he carried him to the bed and threw him down .
"You want to play games?" Remus asked darkly, crawling over him, eyes blown wide with lust and something more dangerous. "I’ll remind you who you belong to."
His hands were everywhere — ripping open Regulus’ shirt, dragging nails down his chest , biting at his throat like he was marking his territory.
Regulus whimpered, head thrown back, fully giving in now. "Remus—"
"No," Remus cut him off, voice low and commanding. "Say it again."
"I’m yours," Regulus panted.
"Again."
"Yours."
Remus smirked darkly, finally freeing them both from their clothes, hands gripping Reg’s thighs tight enough to bruise.
"I’m gonna fuck you so hard you’ll forget anyone else exists."
Regulus bit his lip, grinning lazily. "You think I could ever forget you?"
Remus stilled for a second, something softer flashing through his eyes — but then it was gone, replaced with raw hunger .
"Good," he whispered, leaning in close. "Because I’m never letting you go."
And then he was slamming into him , hard and fast, holding his wrists pinned above his head , teeth sinking into his shoulder.
Regulus moaned loud, head thrown back, completely wrecked for him.
"Mine," Remus growled with every thrust, over and over like a mantra.
"Yours," Regulus gasped back, over and over, until that was the only word he knew.
Remus kissed him hard, desperate and hungry, like he was trying to devour him whole.
"Mine," Remus whispered again when they both finally broke apart, panting. "Forever."
Regulus smiled, breathless and sated. "Forever."