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The class was loud in the way only third-years could be loud—half excitement, half terror.
Remus Lupin leaned against his desk and watched the chaos unfold with patient amusement as Neville Longbottom narrowly avoided tripping over Dean Thomas while trying to get a better look at the wardrobe standing at the front of the room.
Inside it, the boggart rattled violently.
“Settle down, settle down,” Remus said mildly.
The wardrobe shuddered again at the sound of thirty students collectively holding their breath.
Hermione Granger’s hand shot into the air before Remus had even asked a question.
“Yes, Hermione?”
“A boggart is a shape-shifting non-being that assumes the form of whatever most frightens the person confronting it.”
“Excellent,” Remus said warmly. “Five points to Gryffindor.”
Remus pushed himself away from the desk. “Now, the trick to defeating a boggart is simple—laughter. We force it into a shape that is amusing rather than terrifying. The incantation is Riddikulus.”
The wardrobe banged hard enough to jump several students.
Lavender squeaked.
“Now,” Remus continued calmly, “we’ll proceed one at a time—”
The wardrobe burst open.
A silver-white hand shot out through the crack.
The room dropped ten degrees instantly.
Harry froze.
No.
No, not here—
A rattling breath filled the classroom.
The students around him stumbled backward as a tall, hooded figure began to emerge from the wardrobe, skeletal hands stretching from black robes.
A dementor.
Harry’s ears filled with screaming.
His mother begging.
His own heartbeat thundering.
And then—
Remus moved.
Quick as lightning, he stepped directly in front of Harry, wand raised sharply.
The dementor vanished.
The class gasped.
For one terrible heartbeat, Remus prepared himself to face silver light and his own reflection twisted into fur and teeth.
Instead—
The dementor dissolved.
The black cloak peeled away like smoke.
And Sirius Black stepped out of the darkness.
Sixteen years old.
Laughing.
The classroom vanished from Remus’s awareness.
Sirius stood lazily against the wardrobe frame in Gryffindor robes, dark hair falling into his eyes, all sharp smiles and careless beauty. Exactly as he had been before Azkaban. Before betrayal.
Before everything ended.
“Oh, baby,” Sirius drawled, grinning wickedly, “I’m your biggest fear?”
A few students snorted nervously, confused.
Sirius pressed a hand dramatically to his chest.
“I’m touched.”
The voice.
God.
It sounded exactly right.
Warm honey and smoke and mischief.
Remus forgot to breathe.
His wand trembled violently in his hand.
Because this wasn’t merely Sirius Black.
It was his Sirius.
The boy who kissed him behind the Quidditch stands with reckless laughter still caught between his teeth.
The boy who had looked Remus in the eyes and promised, You know I’d never hurt you.
The boy who had betrayed Lily and James.
The boy Remus had failed to see clearly at all.
Around them, the classroom had gone silent.
Bog-Sirius tilted his head.
“What’s wrong, Moony?” he asked softly.
The nickname struck like a blade between the ribs.
Remus felt sixteen again in the span of a heartbeat.
“You thought I loved you back, didn’t you?”
A collective inhale swept through the students.
Harry stared openly now.
Remus couldn’t move.
Couldn’t think.
Because that — that — was the true shape of it.
The unbearable knowledge that he had loved Sirius Black so completely that he had ignored every warning sign. Every secretive glance. Every disappearance. Every lie.
Even after the Potters died, part of him had still waited for someone to say it wasn’t true.
That Sirius had a reason.
That Sirius would come back.
That Sirius would choose him.
Instead, Sirius had laughed while Peter Pettigrew and twelve Muggles died screaming.
Remus swallowed hard.
Bog-Sirius sauntered closer.
“You know what the funniest part is?” he said conversationally. “They all thought it was you.”
Remus flinched.
“Not Lily, maybe,” Sirius mused. “But the others? Dumbledore? The Order?” His grin widened cruelly. “Poor Loony Lupin.”
A few students looked deeply uncomfortable now.
Hermione seemed horrified.
Harry looked pale.
“You trusted me anyway,” the boggart whispered. “You loved me anyway.”
The words hollowed Remus out.
Because yes.
Yes, he had.
Even now, some awful broken piece inside him still did.
The boggart stepped closer still until Sirius’s face was only inches away.
“So tell me, Moony,” he murmured, eyes glittering, “which scares you more?”
Remus couldn’t breathe.
“That I betrayed you—”
The grin sharpened.
“Or that you still wish I hadn’t?”
Something inside Remus cracked.
Enough to remember that this thing in front of him was not Sirius.
Not really.
Because the real Sirius had never looked at him with cruelty.
Recklessness, yes.
Fury. Jealousy. Stupidity.
But never this calculated malice.
The real Sirius had held him together after transformations with blood still under his fingernails from becoming Padfoot.
The real Sirius had kissed every scar like he could erase them.
The real Sirius had looked at Remus like he was something worth loving.
Which meant—
Remus’s fear wasn’t Sirius Black.
It was that none of it had ever been real.
His hand steadied.
Slowly.
Deliberately.
Bog-Sirius noticed.
The grin flickered.
“Oh,” Remus said quietly.
The classroom leaned in.
“I see.”
Pain still sat in his chest like shattered glass.
But alongside it came something sharp enough to cut through the panic.
Anger.
Not at Sirius.
At himself.
Years of grief. Years of loneliness. Years of punishing himself for loving someone who might never have loved him back.
And for what?
A monster in a wardrobe.
Remus lifted his wand.
The boggart sneered instinctively, sensing the shift too late.
Then, with a voice steadier than he felt:
“Riddikulus.”
There was a loud crack.
Suddenly Sirius’s elegant robes transformed into absurdly frilly pink dress robes complete with puffed sleeves and enormous glittering bows. His hair exploded outward into ridiculous curls adorned with tiny singing birds.
The boggart blinked.
Then one of the birds screeched off-key directly into its ear.
The classroom erupted.
Dean doubled over laughing.
Parvati shrieked.
Even Hermione made a startled choking noise.
Bog-Sirius looked outraged.
“What have you DONE to me?” he cried in horror as the birds began singing a dramatic operatic ballad.
Ron slid halfway off his desk laughing.
And just like that, the fear cracked apart.
The boggart spasmed wildly, shrinking back toward the wardrobe.
Remus slammed the door shut.
Silence fell, broken only by scattered giggles.
His hands still shook.
But he was standing.
After a moment, he turned.
Every student stared at him.
Harry most of all.
Remus cleared his throat.
“Class dismissed,” he said gently.
Nobody moved at first.
Then chairs scraped cautiously across stone as the students filed out, whispering furiously.
Harry lingered by the door.
For a second, Remus feared the boy would ask questions he could not answer.
Instead Harry only said quietly, “Professor?”
Remus looked up.
Harry hesitated.
“That wasn’t real.”
Remus managed a faint smile.
“No,” he said softly.
It wasn’t.
But later that night, alone in his office with the moon rising silver beyond the windows, Remus would sit awake far too long wondering which part frightened him most:
That Sirius Black might never have loved him.
Or that, despite everything—
Remus Lupin still loved him anyway.