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2026-09-04
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2026-10-23
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13/?
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a demon, a curse

Summary:

Megumi Fushiguro... is missing.
More than that, Megumi Fushiguro has fallen through the shadows of the worlds and ended up in an adjacent reality-- in Demon Slayer.
Taken in by the Corps, under the protection of the Hashira, Megumi slowly relearns what it means to live for himself, all while climbing the ranks with a mission to help the Corps defeat Muzan.

(Meanwhile, back home, Satoru wakes to a glaringly Megumi-less world, freaks tf out, and will stop at nothing to get his kid back.)

--

essentially Megumi falling into kny :)
(and satoru having an aneurysm over his missing child)

Notes:

hi hello and welcome!!!
i've had this idea for a while now, and i hope you guys enjoy it as much as i do!
jjk is my beloved and demonslayer is my other beloved and yeah im excited abt this haha <33

Chapter 1: shadow breathing, ninth form

Notes:

(See the end of the chapter for notes.)

Chapter Text

It's quiet.

Too quiet.

Dark blue eyes stare blankly at the night sky, a mess of stars and broken moonlight obscured by the wide branches of the towering trees around him. Despite the slightly wind feathering his cheek, lightly caressing his hair-- it's silent.

A held breath. One of fear. The trees, the leaves, they know.

Death has come.

The boy-- he can't remember his name. Can't remember anything. His head aches, a deep, throbbing pain that starts at his temple and the base of his skull before radiating outwards, scattering any thoughts that struggled to piece themselves together.

His whole body is in pain, actually.

He attempts a shaky exhale. It's more of a pained wheeze than anything, eyes pressing tight as his side burns in agony. His stomach, the tender spots beneath his armpits, the side of his face and beneath his eyes-- they all share a deep, scalding pain, as if someone has taken a knife to his skin and ripped it open and dug their fingers into the open, weeping wound, tearing the skin further and further apart, only for the wounds to be crudely sewn shut and left to fester and rot with infection.

Something wet drips down his cheek.

Tears?

The boy manages to lift a hand, trembling as it is, and wipes at his cheek. Brings it to his eyes.

Blood.

Red and warm and sticky against his hand.

Thud.

Footsteps. Large, and loud.

Whether it is himself that is shaking or the ground, he cannot tell. His gaze, half-lidded and blurred, slides to the shadows of the trees. The clouds shift, and a slant of moonlight falls fully onto the figure breaking through the tree line, illuminating their features.

Thud. Thud. Thud.

It is monstrous, this thing.

(Curse, his mind whispers-- it's a curse. But the thought slips away like a leaf in a flowing river.)

Skin the color of jaundice, crisscrossed with bold, black lines, running over their sharp features and bare chest and muscled arms. Its eyes are closed, white markings on its lids. Lumps bulge beneath their skin-- on their collarbone, across their hip, their forearm and wrist, their neck-- almost pulsating in the low light.

It reeks. Sickly-sweet. Rot and honey.

A thin, needle-like weapon is cradled loosely in their hand. The boy watches as a liquid slowly gathers at the tip before dripdripdripping onto the ground. Watches as the grass sizzles and smokes before turning black as ash.

Thud. Thud thud.

It inhales deeply. Opens its eyes.

Two kanji are inked into them.

Lower Six.

It fixates its gaze onto the boy. Its lips draw back into a wide, fanged smile, saliva dripping onto its chin.

"Marechi."

The boy's eyes widen, a prey fear settling deep into his bones.

And everything goes black.

 


 

Thud.

His lungs ache. Something-- something's broken. A wet cough escapes his lips.

The taste of metal coats his throat and mouth. Drips out of the corner of his lips.

Thud.

Something digs into his heel. A hand?

He is being dragged.

A rock digs into his skull. His arm, limp and numb and useless, catches on a stray branch.

Thud.

He can't open his eyes. He tries, he does, but he is tired. So, so tired.

Thud.

The rough dirt beneath his back gives way to uneven stone.

He knows the wetness at the base of his skull is blood.

Thud.

Everything is weightless. All sensation, all pain-- it leaks out of him.

The grip on his ankle vanishes.

His head and back no longer dig into stone.

Crack.

Something slams into rock-- it takes a moment before the boy realizes that something was him, and he writhes in agony. Curls over himself in pain, everything trembling and shaking and on fire if he has not lost feeling in it yet.

Someone is crying. No. Multiple someones.

A small hand presses against his throat. Two fingers search for a pulse.

Words float around him.

More hands tug at his clothes, at his limbs. The whispers grow panicked, desperate, and the fingers dig into his throat, searching, searching for a pulse.

None is found.

 


 

Drip.

          Drip.

                      Drip.

Something wet plops against his cheek.

It's quiet, now. But different than before.

The boy takes a shallow, pained gasp, then curls over himself in a violent, hacking cough. Blood splatters against the dark stone-- his eyes are open, when did he--? -- and his fingers dig into the rock, white-knuckled and raw and bleeding.

Behind him, someone gasps. There's a slight patter of footsteps, light, so much lighter, child-like and panicked, and then there is a hand pressing between his shoulder blades and rubbing soothing circles. He does not understand the words floating around him, but his shoulders loosen at the gentle tone, the reassurance of it.

More footsteps sound, and the boy lifts his head.

Two pairs of dark, jade green eyes stare back at him.

A girl, no older than eight, dressed in a torn green-and-yellow kimono. Dried blood blossomed across the left leg and shoulder, but her face bore no sign of pain. Her cheeks her ruddy and dirt-stained, old bruises apparent along her jaw. A single clip was tucked into her hair. At her side, a boy, maybe five, clutched at her kimono, small fingers clinging desperately to her tiny frame. He was dressed similarly, though his kimono was more dirt stained than bloodied, and ripped open at the sleeves.

Siblings.

A pang of-- something, something deep and awful and old and painful, dug into the boy's heart.

(A memory tugs at the corners of his mind-- a young girl with soft brown hair pulled back into a ponytail, twin strands falling out and framing her face. She holds him close to her chest, whispering into his ear as he shakes, his own eyes fixed on the screaming, squelching monsters that lurk at the corners of their apartment, long since abandoned by the man they once knew as Father. She can't see them, these monsters, but they tear at his skin as he sleeps and when he wakes his arms are a mess of bloodied marks. He thinks he is crazy. But the girl-- her name is-- she is his older--)

Daggers dig into his eyes, his skull, and the boy hisses in pain, the brief flicker of a memory gone and forgotten once more.

Slowly, he managed to turn his head to the side.

Brown eyes studied him from pale, bloodied skin, delicate features framed by ink-black hair. A girl, not even nine, dressed in a dark blue kimono and a darker shaded haori. The girl's hand lifted from his back, then pressed lightly against his throat, sitting there for a long moment as she counted his heartbeats.

Seemingly satisfied, the girl shifted, sitting back on her heels. Stared at him.

"You're alive."

It was a statement of fact. The boy could hear the slight edge of surprise to her tone, as if the very act of him being awake-- coughing up blood and trembling in pain-- was something she never thought would happen. The boy opens his mouth. Closes it. Swallows thickly.

"Yeah."

His words are more of a croak, his throat rough and torn and raw. A flicker of surprise lights up the girl's eyes, and she exchanges a glance with the siblings, something unreadable in their gaze, before turning back to him.

"What village are you from?"

At that, the boy's brows draw. He searches his memory, a man desperately dragging a net through still waters. He does not know. He does not know anything at all.

"I don't-- I don't know." The boy presses a shaking hand to his chest. Is his heart suppose to be beating this fast? Wild like a galloping horse? Frantic? Panicked? "I don't-- I can't remember."

Understanding, maybe, or pity, settles on the children's faces.

The younger girl nods her head. Spoke with the usual lacking tact that children always seemed to do. "Your skull cracked against the wall when the demon threw you."

Ah.

Well.

That answered one thing, the boy supposed.

He took another shallow breath, lips twisting in pain, and managed to sit up. He waved off the older girl's hands, hovering inches from his body as he nearly fell back over, and steadied himself, looking around.

They were in a cave.

A shallow one. Not even fifty meters away was the entrance.

"Don't."

The boy turned back towards the children, gaze falling on the child still clinging to his sister. His eyes had gone wide with terror, and he pressed tighter to his sister's side.

"It-- it'll find you. An'-- an' eat you."

A haunted look passed like a shadow across the children's faces.

It seems there had been others, too. Others that had thought to escape just as he had.

Strangely, the boy does not fear this monster. If anything he is... ambivalent to it, like one would be towards an inconvenience rather than a death sentence. Somewhere, deep inside him, he knows-- he has faced worse. Has survived worse.

(The blade is heavy in his hands. His lungs shake from exertion, sweat dripping down his hair line and into his brows and eyes, running down the side of his face. Too easy. He exorcised it too easily, too quickly. He looks around the cave, eyes widening at the cursed womb pulsating at the center of its ceiling. There is a squelch-- wet, and disgusting-- and a familiar, grinning curse stares at him in glee.)

The boy blinks.

A memory?

He feels so disconnected from it, though. Like watching the movements of a stranger rather than himself.

"Where are we?" the boy asks, ignoring the itch in the back of his mind.

"It's cave," the girl in the green kimono supplies. "It's where it... keeps us. Until it gets hungry."

So the four of them were food, then.

Shakily, the boy stands. His legs threaten to give out, but he catches himself on the wall, one hand digging into the rough stone.

"What-- stop!"

The older girl tugs at his arm, eyes wide with fear. "You need to sit down, you're still--"

"I'm fine."

The boy shakes her off. Takes slow, halting steps towards the other side of the cave, where a pile of bones-- skulls and ribs and femurs and fibulas tossed together and stacked in a small mountain.

It reminds him of something.

Of what, though, he doesn't know. Doesn't remember.

His fingers close around a broken sword at the pile of bone's base. He tests the weight in his hand.

It is lighter than what his body remembers-- his muscles move without thinking, shining the blade in clean, steady strikes, feet moving in a dance long since drilled into him.

Everything burns. His vision blurs.

But the body ignores it.

He presses his eyes shut, breathing deeply as he shoves the pain down. Folds it like paper into smaller and smaller shapes until it is something he can crush beneath his heel for a bit. He grabs the sword's sheathe, looping it around his waist, the sword still in his hands.

"What are you doing?"

The boy opens his eyes, meeting the wide, frightened gazes of the three children. He crouches, setting the blade on the ground beside him.

"I am going to exorcise the monster."

(The curse, his brain supplies once more. It is a curse. But despite his instincts screaming that name at him over and over again-- the boy doesn't accept it. Won't. Because it is wrong. Whatever that thing is... it is not a curse.)

His hands come together-- palms pressed against one another perpendicularly, his left hand encircling his right, whose fingers are splayed and thumb sticking up.

Nothing happens.

The boy blinks. Tilts his head.

Something was-- something was supposed to happen. At least, he thought.

He shakes off the strange, sticky feeling, and grabs the sword. A rush of energy, vast and deep and endless as the seas, sparks, and he nearly drops it, staring wide-eyes at the blade. He takes a shallow breath-- wrong. He feels it. Knows it. His grip tightens on the sword, and he takes a deep, even breath.

The energy thrums, raging waves tossing against one another.

It felt... right, this energy. Like a dream half-remembered.

(A boy, perhaps a year older than him, unsheathes his katana, holding the blade out for him to inspect with a smile. Dark hair falls into his eyes, deep eye-bags from exhaustion coloring his face.)

Okkotsu. That boy-- his name is Okkotsu. Yuta. Yuta Okkotsu.

The boy's eyes widen.

That's... something. A step in the right direction, at least.

He stares at the blade once more, then looks back to the kids. Stands.

"Follow me."

The kids blink at him. Violently shake their heads.

"Are you even listening?" the older girl hisses, cheeks reddening with anger. "It will kill you! Kill all of us! It will hunt us down and eat us and--"

"You'll be eaten if you stay."

The boy lifted his sword. Turned on his heel. "I'll protect you. Now move."

The kids all looked at each other-- then scrambled to their feet, stumbling forward and after the boy. He felt a small hand grip his pants, and he looked down, the little boy's gaze trained on the ground as his hand curled tighter into his pants.

He leads them out of the cave and into the small, grassy clearing before it. A crow caws, shifting on a tree branch, and his eyes flick to it for a beat before he lifts his gaze to the sky. Looks to the stars. His gaze catches on a constellation-- the Southern cross.

Again, something itches in the back of his mind.

Does he... know this?

Knew it, once?

"What's this?"

A low, amused voice ripples through the air. The kids shriek, tripping over themselves as they duck behind the boy's body. The boy doesn't flinch, simply lowering his gaze towards the voice and lifting his sword at the shadow emerging from the woods.

Kanji inked eyes stare back at him.

The monster's gaze drops to the children clinging to his frame, then to the broken blade in his hands. Its lips tug back into a wide grin, and a laugh escapes it.

"How wonderful! It has been so long since my prey has wanted to play."

The monster flicked its wrist, the needle-sharp weapon dripping with poisonous liquid appearing in its hand. "Perhaps I'll make you into one of my minions, hmm? I could always do for another member of my hive."

The boy ignores the monster's words. Focuses his thoughts on the blade in his hands, the energy thrumming through his veins.

His body knows.

This monster... this opponent... is weak.

It rambles on. The boy ignores it.

He closes his eyes. Exhales deeply, letting the energy pooling in his gut and sword gather like a swirling maelstrom, growing strongerstrongerstrongerstonger--

"Shadow breathing."

A blur of motion. The shink of a sword unsheathing.

"Ninth Form."

A snarl. Shadows writhe, twisting and stretching as a lithe, feline form claws itself from the inky depths.

"Tiger Funeral."

Silence.

Nothing, not even the wind, dares move.

Shadows settle.

Thud.

The monster's head falls to the ground, open-mouthed and shocked.

"How... how?"

The boy sheathed his sword. Ignored the screams of outrage and murder from the monster. He exhaled slowly, turning on his heel. Watched as the still-screaming monster began to dissipate into dust, until its entire body vanished without a trace.

The words felt foreign on his tongue. Off-kilter.

It should've been his hands, not this sword. Should've been his right hand curled into a half-opened fist, his left sitting atop it, fingers played, saved for an arched pointer finger. It should've--

the world tilted sideways, and the boy collapsed to the ground.

The pain he had shoved down now returned tenfold, a burning agony that felt like his entire body had been set aflame and ripped open and stabbed over and over and over again. His breaths turned to strangled gasps, wet, and thick, chest heaving as he coughed up, threw up, blood, every part of his body trembling.

His vision swam.

Screams, and shouts, and the loud cawing of crows mixed together and rippled around him.

Small fingers pressed against his throat.

Something wet and red dripped into his eyes. Dripped from his nose and mouth.

His fingers slipped from the blade. His eyes rolled into the back of his head.

Thud.

 


 

The Master was late.

Had it been Tomioka, or Tokito, it would have been of no concern to the Hashira, now gathered in the sitting room awaiting the Master's arrival. Tomioka rarely ever arrived on time-- whether that was because he thought himself above the rest of them, and therefore their joint meetings, or his aged, somewhat unreliable crow, they didn't know-- and Tokito... Tokito often wandered in at some point. Eventually.

However, it was neither Tomioka nor Tokito that was late. It was the Master.

Oyakata-sama.

Oyakata-sama, who was never late. Oyakata-sama, who was as dependable as the rising sun.

"What if something has happened?" Kanroji asked, glancing nervously towards the door that the Master typically entered through. "What if Oyakata-sama has gotten worse?"

"Lady Amane would inform us, if that were the case," Uzui said, reaching out to set reassuringly pat her head. "Don't worry. I'm sure Oyakata-sama has simply been delayed."

"But--"

Kanroji broke off, all nine gazes snapping towards the now opened door. Two of Kagaya's daughters knelt at either side of the entrance, heads dipping in slight bows as their father and mother stepped into the room. The Hashira followed suit, bowing their heads as Kagaya knelt.

A soft, gentle smile tugged at the man's lips. "My children. How wonderful it is to have all of you here. It brings me great joy to see our ranks whole and unharmed."

Kagaya raised a hand, and a crow flew into the room from the corridor he had just entered from, his daughters shutting the door behind the bird. It settled onto Kagaya's hand, ruffling its feathers slightly.

"Go on," Kagaya urged, "Tell my children what you have told me."

The crow puffed out its chest. Flapped its wings.

"Caw! Lower Moon Six has been defeated! Lower Moon Six!"

A shocked silence fell upon the room at the bird's cry.

The Hashira looked towards each other, the same question heavy in their eyes.

Not one of them had slain Lower Moon Six.

Which begged the question-- if it had not been a Hashira... then who?

"Oyakata-sama--" Rengoku leaned forward, eyes wide "--who has slain the demon?"

"Caw! A civilian! A civilian has defeated Lower Moon Six!" The crows flared its wings, drowning out the mix of shock and horror and disbelief of the Hashira. "A civilian utilizing the Shadow Breathing technique! Caw!"

Silence fell back upon the Hashira once more.

A civilian. Shadow Breathing.

It shouldn't be possible. A civilian shouldn't be able to utilize a breathing technique-- shouldn't be able to utilize one that didn't exist.

"Caw! Defeated in a single strike! Caw!"

"Impossible!"

Shinazugawa stood, anger written across his features. "Master, the crow must be mistaken. There is no possible way a civilian defeated a demon, let alone Lower Moon--"

Kagaya lifted a hand.

"There are three eyewitness accounts, aside from that of my crow. Three children, all of Marechi blood, who shared the same story. The Shadow Breather defeated the demon in a single strike using a broken blade."

"Broken...?" Kanroji whispered, eyes wide.

"Where is this civilian?" Shinazugawa demanded, "And how have they gone unnoticed by the corps all this time?"

Kagaya tilted his head towards Kocho, who bowed her head before speaking.

"The boy is recovering at the Butterfly Estate." She hesitated for a moment, before adding-- "His injuries were... alarming, Master. And based off of the children's accounts, none of them, save for when he was thrown against the wall, were from the demon."

"Boy?"

Himejima looked towards Kocho. "How old is this civilian?"

"At my best guess, I would say... fifteen. But his body shows signs of childhood malnutrition, which may impact my estimation."

"Namu Amida Butsu," Himejima murmured, tears pooling in his eyes and running down his cheeks. "What is the child's name, so that I may pray for him?"

"We don't know."

"Huh?" Shinazugawa stared at her. "You don't know? You didn't ask him?"

"It's not that."

Kocho curled her fingers into her haori. Exhaled slowly.

"The boy... is comatose."

Notes:

another longfic, ahahaha welp. anyways. this is so self-indulgent but i hope you guys will enjoy it too.
hopefully i characterized the kny characters ok, its my first time writing for them so lmk what u think!!
kudos and comments are always appreciated! especially comments, they really do make my whole day and i love hearing from you guys!

taisho era secret: the lower moon six demon was inspired by the zombie parasite bee! real creepy.

have a great morning/afternoon/evening/whenever you're reading this! <3