James returned to Hogwarts for sixth year with a shiny new captain’s badge, a stomach full of unease, and a head that wouldn’t quiet.
It had been a slow summer—on the surface.
Warm days. Long evenings. Quidditch in the orchard with Sirius. Laughter, shared meals, the comfort of familiar spaces. But beneath all that, something had shifted. The house felt different.
His parents were uneasy. Not overtly. Not in ways James could name. But he caught it in their glances—in the way conversations stopped too quickly when he walked into the room. His mother kept the wireless on low in the kitchen, even when she wasn’t listening. His father took the morning paper into the garden and read it in silence, jaw tight, cup of tea going cold beside him.
There was a name James heard once—late at night, long after his parents thought he and Sirius were asleep.
The Order.
He didn’t know what it meant. Not exactly. But it stuck with him.
There were other things, too. Neighbours who’d gone on holiday and didn’t come back. A shop in the village that closed suddenly, the windows dark for weeks. His mum, who had been talking about retirement, pulling longer shifts at the hospital.
Something was happening. And even if no one had told him what it was—he could feel it. Like a storm building behind the hills.
And on top of that, there was Sirius.
Something had shifted between them—small and sharp, lodged just beneath the skin. The easy rhythm they used to fall into without thinking had faltered. Conversations paused more often. Jokes didn’t always land the way they used to.
They didn’t talk about what had happened with Snape. But they all felt it. Remus was quiet. Peter was twitchy—overly eager to smooth things over, like a child trying to tape broken glass back together.
Sirius was louder. Sharper. He performed his usual recklessness with such intensity it felt like a dare— watch me pretend I’m fine until it kills me.
And James?
James let him.
But in the quiet moments—in the dark, with nothing but the hush of wind outside the window—he kept circling the same question:
What does it mean to be a good person?
No answer came.
Only the question, echoing on a loop.
It followed him onto the train and back into the castle.
A silent ghost that trailed him through the corridors of sixth year.
It was the third week of term when it happened.
Sunlight fell soft over the courtyard stones. The last of summer’s warmth clung stubbornly to the air. James was walking with Marlene and Peter, halfway between Herbology and the Great Hall, when the murmurs reached them—a low hum, too focused to be casual.
A crowd had gathered. Tight. Intent.
James moved closer. Not out of curiosity, but instinct—something in the atmosphere felt wrong, warped, like the moment before a lightning strike.
Then he saw them.
Two figures in the centre of the circle.
Thaddeus Mulciber—broad-shouldered, thick-necked. Wand out, sneering.
Opposite him: Evan Rosier.
Wand already raised. Calm. Still. Expression unreadable.
A thread of danger laced the air—coiled and tightening.
James moved without thinking.
Forward, through the press of students, pushing between bodies and voices, shouldering past a blur of green and black. He didn’t have a plan. Just a sick, sudden certainty that he didn’t want to watch Rosier get hexed into the flagstones.
Mulciber was a seventh year. Vicious. He hexed dirty, always had. And Rosier—
James didn’t stop to consider what he was doing. He just moved.
And then a hand caught his wrist.
Warm. Strong. Deliberate.
James turned. A petite girl looked up at him. Long blonde hair. Ravenclaw tie. Too-blue eyes.
Rosier’s sister.
"Don't," she said softly. "He knows what he’s doing." Her smile—cool and faintly amused—reminded him, unsettlingly, of her brother. She slipped her arm through his, linking them as if they were partners at some formal event rather than witnesses to a duel. Holding him in place.
"Just watch," she murmured, turning back to the duel. “Trust me, it’ll be good.”
Mulciber struck first.
A brutal slash of his wand—downward, fast—ripping the air with a sound like breaking glass. The spell cracked toward Rosier, loud enough to make several students recoil.
Rosier didn’t flinch.
He stepped to the side with surgical precision, pivoted cleanly, and raised a ward that absorbed the impact like it was nothing. It was effortless—less a block than an inevitability, like he’d seen the move hours in advance.
Mulciber surged forward.
Pinning hexes, tripping jinxes—nasty, mean-spirited magic fired like bullets. One was bright and thin and vicious, and James was almost certain it was designed to draw blood.
Rosier deflected them all.
He didn’t return fire. Not properly. Just enough to keep Mulciber in check—light tripping hexes, a jolt of static to the shoulder. But no malice. No vengeance. Just control. Cold, methodical control.
James forgot to worry.
He forgot to move.
He just watched, transfixed.
Rosier didn’t fight like a schoolboy. He fought like a duellist trained for war. No flourishes. No wasted motion. Just tight, refined defence—Mulciber was losing, and he knew it. Rosier was straight-up playing with him,
It showed in his footwork. His breathing. Steady, easy. Not even breaking a sweat.
Until something changed.
Mulciber snarled—low, guttural—and flung something twisted and foul from the end of his wand. It struck the stone beside Rosier and crawled. The floor cracked. Black veins spidered through it, pulsing like living rot. Thick smoke, low to the ground, curling like ink in water. It hissed over the stones, tendrils reaching for ankles. Several students screamed. James felt it in his spine—a creeping cold that clung.
The crowd lurched back.
That wasn’t duelling magic. That was something worse. Something not meant for schoolchildren.
Rosier’s wand came down—clean, an arched sweep—and the smoke peeled back as if repelled by some unseen wall. Then, calmly, he raised his wand again. A bolt of light struck Mulciber square in the chest.
He staggered.
Exposed. Vulnerable.
James tensed—waited for the strike that would end it. Waiting for Rosier to finish the fight.
But he didn't. He just stood there. Expression unreadable. Waiting.
Mulciber Recovered. Summoned a nest of serpents from the stone. They slithered up in a living knot of scale and hiss and hatred—barrelling toward Rosier in a tangle of fury.
This time, Rosier moved. And he moved fast.
Green fire exploded from the ground. It twisted like silk in the wind, curling forward in a wave, silent and eerie. The snakes shrieked—actually shrieked—as the fire devoured them. Not burned. Consumed. They unravelled into ash and vanished.
The flames twisted in mid-flight—coiled inwards, curling into a perfect circle around Mulciber. A ring of fire holding him in place.
Mulciber stumbled, nearly tripping over his own boots as the wall of green flame rose up around him. He raised his wand—snapped through a complicated sequence of movements.
The ring flickered—flames dancing higher in silent flickers, leaping as if someone had thrown kindling on them. Mulciber stood frozen at the centre, sweat gleaming down his neck, his wand trembling in his fist.
“Fucking bastard,” he spat, voice raised—anger and something else—maybe humiliation? Fear? James wasn’t sure.
Rosier didn’t move. His wand lowered, posture loose but taut with held restraint.
“Pack it in,” he said, voice flat and even. “I’ve got you and you know it.”
Mulciber sneered through gritted teeth. “Didn’t think you had it in you. Your father must be proud. Pity he didn’t teach you how not to be a fucking disgrace while he was at it.”
Rosier’s jaw clenched.
“Be careful,” said Rosier, and for the first time James actually believed Sirius when he said Rosier was a threat to society, he looked downright dangerous, his expression hard—eyes fixed on Mulciber. “Be very careful about what you say next.”
But Mulciber only smiled wider. “Worried what I’ll let slip?” he hissed. “Maybe something about the kind of company you keep? What would your father say if he knew what you and—”
He didn’t get to finish whatever threat he was intending to launch at Rosier.
Rosier didn’t speak.
Didn’t blink. Didn’t even raise his wand.
And yet the fire leapt.
A wall of green erupted—high, violent, final. It surged upwards swallowed Mulciber whole.
A scream ripped through the courtyard. High, raw, inhuman.
James’s stomach dropped. His breath caught in his throat.
Then—silence.
The flames vanished.
Mulciber crumpled.
He was on his knees, pale as chalk, hands clutching at the stones. His wand was gone, vanished, black suit covering the hand that had been holding it. Mulciber gasped, gagged, retched—dry, awful sounds. His entire body shook as he heaved, vomiting onto the flagstones. He looked like he’d been hollowed out; he looked like death warmed over.
Rosier stepped forward and knelt beside Mulciber.
“I warned you,” he said quietly—so quietly that James, only a few feet away, had to strain to catch the words. “I told you, very clearly, not to fuck with me. And you did it anyway.”
Then Rosier stood, turned, and walked away.
The crowd parted, silent.
Slughorn came running, calling for space, for calm, for someone to fetch Madam Pomfrey. But James barely noticed. His gaze remained fixed on the archway where Rosier had vanished, the image of green flame still imprinted behind his eyes.
That night, James sat in the common room, staring into the fire.
Across from him, Remus and Peter were locked in another slow-burning chess match. Their murmured disputes rose and fell like low tide—Pete groaning every time one of Remus’s knights trampled a pawn, Remus responding with quiet satisfaction. Sirius lounged sideways in the nearest armchair, limbs draped carelessly, his eyes half-lidded. He hadn’t said much since dinner. None of them had, really.
James was still thinking about the duel.
He’d been thinking about it all day—and he wasn’t the only one. The castle buzzed with rumour. Since supper, James had overheard at least three retellings, each more absurd than the last. One had Rosier exploding Mulciber’s eyeballs. Another claimed he’d set himself alight just to prove he could survive it.
James hadn’t bothered correcting any of them.
Behind him, a familiar cluster of voices drew his attention. Mary, Marlene, and Lily sat on the windowsill couch, talking in hushed tones. Earlier, they’d been discussing Arithmancy—James had half-listened with the sort of vague, automatic interest he reserved for anything involving Lily Evans. But now he caught a name that sharpened his focus.
“Alice was in the hospital wing picking up an allergy draught and overheard Madam Pomfrey talking to Slughorn. They’ve sent Mulciber to St Mungo’s,” said Mary.
“I'm not surprised," said Marlene, "Whatever that spell was, it wasn’t standard duel magic.”
“Did you actually see it?” asked Lily.
“Yeah,” Marlene said grimly. “At first it was just verbal—Mulciber was goading Rosier, and Rosier was mostly ignoring him. Then Mulciber said something nasty about Rosier’s sister and Rosier told him to fuck off. But it didn’t get really bad until—” Marlene paused, and James, who had been pretending not to listen, found himself unconsciously leaning closer.
“Until what?” asked Lily, curious.
“Well,” Marlene said quietly, “Mulciber called him—”
“Called him a faggot.” Supplied Mary.
“Oh,” said Lily softly. Then, in a voice so low James had to strain to hear: “Do you think he actually is—?”
“Who Rosier?” Said Mary sounding amused. “No way. It really pissed him off though, that’s for sure. Told Mulciber if he didn’t shut the fuck up he’d make him—and then they started dueling and well…Rosier made him shut up alright.”
“What did he do, exactly?” Lily asked. “Someone said he tried to burn him alive.”
Mary shook her head. “No—Mulciber wasn’t even burned. Just… sick, afterwards. Shaky. Pale. I don’t know what kind of spell it was. Mulciber conjured a load of snakes, and Rosier lit them up—but not with normal fire. It was green. Burned all the snakes up. Rosier told him to surrender. He didn’t. Kept running his mouth. That’s when Rosier set the fire on him. Not burning, exactly—just swallowing him. Afterwards, he looked really ill.”
“It was scary,” Marlene added. “Really scary. Kind of makes you believe the stuff they say about him—you know?”
Lily tilted her head, frowning slightly. “I wonder…”
“What?” asked Mary.
Lily shook her head. “Nothing. Just a thought.”
Mary leaned in. “Oh, come on. What was it?”
Lily hesitated, then said quietly, “It just sounded like Vellfire. But it couldn’t have been.”
James, who had been listening far too intently to maintain any pretence of distance, spoke without thinking. “What’s Vellfire?”
Lily turned, startled, and glared. “Mind your own business, Potter.”
“Don’t be like that, Evans,” James said, standing and walking over towards where they sat, curiosity outweighing caution. “What is it, then—Valfire?”
“Vellfire,” Lily corrected, still clearly deciding whether to answer. After a pause, she sighed. “Parasitic cursed fire. It feeds on magic—the more magic it consumes, the stronger it becomes.”
James blinked, green flame flaring again in his memory. “Feeds on magic,” he echoed slowly. “When Mulciber cast a hex, it kind of grew…Like it was feeding.” He hesitated, then added, “And—Mulciber’s wand. It was in his hand, and then it wasn’t. Just gone. Ash.”
He looked at Lily. “Would it do that—burn through a wand?”
She nodded. “Yes. But he couldn’t have—”
“I reckon he could,” said James. The conviction in his voice surprised even him. “Rosier’s got a thing for fire,” he added, almost smiling as he remembered the first time he’d met Evan Rosier in detention—when he’d admitted, with no particular shame, that he was there for setting his curtains on fire. Then there were Sirius’s frequent jabs, calling him a pyromaniacal psychopath, and his ongoing insistence that Rosier had once tried to burn him alive in his sleep—it all pointed in the same direction: Rosier had a history of setting things alight.
“If anyone at this school knows how to summon cursed fire,” James said, “it’s him.”
But Lily shook her head, firm now. “No. You don’t understand. You’d have to be insane, or suicidal, to conjure it in a duel. If it turns on you, it doesn’t stop. I’m not sure what it would do to a person—but it would be bad. It’s totally impossible to control.”
James leaned against the wall, arms crossed. Rosier had looked like he was in perfect control of the fire. It had moved like it knew what he wanted—like it was listening.
James frowned.
“It’s a form of Fiendfyre,” continued Lily. “It’s really dangerous. Dark arts. Really dark.”
Marlene and Mary exchanged a look, and then Marlene lowered her voice. “Well… you know what they say about the Rosiers.”
James shook his head. “No? What do they say?”
Marlene’s voice dropped to a whisper, conspiratorial. “That Rosier’s grandmother—his father’s mother—was part of Grindelwald’s inner circle. That she raised both her sons to be Dark wizards. And that Mr Rosier killed his own brother in a duel.”
She glanced around before adding, “The whole family’s supposed to be steeped in the Dark Arts. They say even the Ministry doesn’t know half of what’s in their vaults.”
Mary leaned forward, dark eyes bright. “I heard their manor’s Unplottable. That the Department of Mysteries tried to raid it in the sixties and didn’t come back. Like—no one came back.”
Marlene nodded. “And they can do Blood Magic. There’s that story about the blood orchid on their estate—the one that only blooms when someone dies on the grounds.”
“That can’t be real,” Lily said, rolling her eyes. “Blood Magic’s been banned in England since before Merlin was born.”
Mary raised an eyebrow. “Yeah, well—they aren’t English, are they? French. All of them. The Rosiers—Malfoys, the Blacks, the Lestranges. They all fled France after the revolution—probably brought Blood Magic with them.”
“No one really knows what’s true with that lot,” Marlene said, lowering her voice. “Like Rosier’s mother. Some people think she was part-Veela. That his father bound her with dark magic. Made her serve him.”
“And that she’s not actually dead,” Mary added with a hushed kind of glee—the kind that only the most salacious gossip could inspire. “My mum says they never had a funeral. Just a death notice in The Prophet. But no one ever saw the body. No burial. No wake. She just vanished and no one ever spoke about it again.”
James looked at the three of them. Their faces flickered in the firelight—thoughtful, uncertain, edged with the kind if dark looks that are usually reserved for the most chilling ghost stories you can think of. He didn’t buy it. Not really. People loved to gossip about the old families. Every pure-blood line had its share of shadowed histories and conveniently missing relatives. Even his own family had a few lurid tales floating about—one especially absurd rumour that a Potter ancestor had made a pact with Death itself to preserve the family name. It always came back to blood, power, inheritance.
Most of it was nonsense.
The only part James thought might actually be true was the fire.
That had felt real. Had felt like something truly powerful.
He didn’t speak. Just turned and drifted back to the chair he’d left. Sirius looked up as James dropped back into the seat beside him. “Another failed declaration of love?”
James rolled his eyes. “No. Wasn’t about Lily.”
Sirius glanced sideways, brow raised. “Miracle.”
“It was about the duel,” James said, staring up at the rafters. “They think Rosier’s into the Dark Arts.”
Sirius let out a laugh. “Think? Please. That fucker is a dark wizard in the marking. I would know. The Rosiers and my parents—very cosy. You know his dad killed their mum—Evan and Dora. Did it in cold blood because she was going to leave him.”
Remus looked up, expression horrified. “Really? That’s awful.”
Sirius shrugged. “That’s what my uncle Alphard said anyway. And I believe him—Marcus Rosier is pure evil and his son is exactly like him. They even look the same.”
James frowned, at the words. He didn’t believe Sirius’s claim anymore than he did Mary or Marlene’s. “He didn’t strike when Mulciber was down.”
Sirius blinked. “What?”
“At the end. Rosier had him. Could’ve cursed him to hell and back. Didn’t.”
Sirius regarded him. “He still put him in St Mungo’s, Prongs. That’s not nothing.”
“I’m just saying—Rosier fought fair.” He tugged absently at a loose thread on his sleeve. He wasn’t sure why it seemed important, just that it did.
A silence stretched between them.
Sirius’s voice was quieter now, but no less bitter. “Didn’t know we were taking sides when snakes go for each other’s throats. I know Rosier, Prongs. Trust me doesn’t fight fair when it matters.”
James glanced over. “What’s your problem with him?”
He tried to sound casual, but didn’t quite manage it. The question had been on his mind for a while. So far—as far as he could tell—Rosier actually seemed sort of decent. James had never seen him do anything particularly cruel or underhanded. In fact, he hadn’t seen him do much of anything until today. And what he’d seen during the duel didn’t look like gratuitous violence. It looked controlled. Measured. Rosier hadn’t lashed out—he’d responded. He'd had the chance to hit Mulciber while he was down and he hadn't. Sure there had been the thing with the fire, but that hadn't happened until Mulciber had threatened him with— well James wasn't sure what Mulciber had been threatening him with, something to do with his dad? Anyway, as far as James was concerned, Mulciber had probably deserved it.
Sirius didn’t answer right away. He leaned back in his chair, jaw tight, eyes fixed on some point in the fire. “Just because he’s not loud about blood purity doesn’t mean he’s not one of them, Prongs. He is. Don’t forget that—or who his family is. He’s not a good person.”
James didn’t respond.
A flicker of discomfort passed through him. There it was again.
That phrase.
A good person.
As if it were something fixed. As if it meant the same thing in every context. He wasn’t sure it did.
Mulciber stayed in St Mungo’s for nearly a month.
When he returned, he was quieter. Paler. Thinner. His eyes darted like he expected to be cursed at any moment. The swagger was gone. So was the smirk. He stopped baiting the younger students. Barely spoke.
Whatever Rosier had done, it had left a mark.
And James couldn’t help thinking—maybe that was a good thing.
The rest of the castle moved on.
James drifted through the term in that easy, half-distracted way he did most things. The only thing he really gave his all to? Quidditch and his role as captain. He was proud of it. If there was one thing in the world James Potter took seriously, it was flying. That, and winning.
Gryffindor took their first match of the season against Ravenclaw, 190 to 80, in a match that left James soaked, bruised, and ecstatic. He scored six times, assisted once, and took a Bludger to the ribs with what he described (to anyone who would listen) as “heroic, noble sacrifice” and what Remus described as “you flying like an idiot into someone else’s line.”
Slytherin lost to Hufflepuff in November—barely. Regulus missed the Snitch by inches. Evan Rosier played hard, clean, and clever. James, though he’d never admit it out loud, thought they’d both flown exceptionally well, even if they hadn’t won the game.
Sirius hadn’t been allowed back on the team after the incident with Snape.
And, a small part of James was almost relieved.
Quidditch was just his now. He was captain. His pitch. His team. Something he didn’t have to share with Sirius—didn’t have to mediate or mask around. Something untouched by the tension that had been dragging at them since summer. They weren’t fighting, exactly, but something between them had cracked. A fracture neither of them knew how to name, let alone fix. At least on the pitch he could let it go, could just fly.
It was just before Christmas when James saw Rosier again.
They crossed paths outside the library. James was heading in, a Transfiguration text tucked under one arm. Rosier was coming out, walking in step with his sister, their heads bent in quiet conversation.
James slowed. No real reason. Just a flicker of impulse. Recognition, maybe. Residue from the match. “Good game on Friday.”
For a moment, Rosier’s expression flickered—surprise, guarded and fleeting, like he wasn’t sure if James was being sincere or not.
“That block on Diggory’s reverse swing,” James added. “Smooth.”
Rosier ducked his head, when he looked up he was smiling, a proper smile. Not a smirk. “Cheers, Tosspot.”
James nodded, feeling a bit embarrassed and then continued in his way into the library. He didn’t know why he’d said anything. Not really. It hadn’t been calculated. Just instinct. Reflex. But it stuck with him longer than it should have.
He told himself it wasn’t a big deal. He was Quidditch captain, after all. Recognising talent—even across house lines—was part of the role.
Christmas passed quietly.
Sirius came home with him, as always. They didn’t talk about Hogwarts much. Didn’t talk about anything real. Instead, they flew, played chess badly, made the wireless crackle with experimental charmwork, and pretended—for a little while—that they were still invincible. Still on the same page.
James didn’t bring up the team or what it was like flying without Sirius. Sirius didn’t bring up Snape.
It was easier that way.