[fic wip/abandoned] kny, genya/tanjiro, tanjiro-is-a-demon au

[hexmix]

MAN. i have a heck of a lot of unfinished kny fic that's never gonna get finished bc i now kinda hate the manga and definitely hate the fandom, but i also still really like a lot of what i was working on back in 2019 when i still liked the series.

anyway, here's 12 pages of what was supposed to be a tanjiro-is-a-demon au and ended up being more of a genya-centric character piece. there's a tense shift after the first scene that i haven't fixed, and then the second half becomes more half-scenes with no clear chronology, but it was fun for me to reread this bc it's basically just "remember how much you loved genya and mitsuri? bc it was a heck of a lot." i also left in a note 2019-me left to myself bc i think it's funny.

warnings for: cuts off abruptly; gore/dismemberment; what's close enough to count as cannibalism (lite)

Genya was aware that his world was considerably narrowed. Himejima felt the need to keep telling him so, but his disinclination to change wasn’t because he was unaware, as his master apparently thought. Genya’s world had been forcibly narrowed for him, years and years ago, and he simply never saw the need to broaden it. He’d fucked everything up so horribly that a world consisting of only a single person already seemed impossibly huge.

 

He took the missions they gave him, though. Sometimes it seemed like just another obstacle between him and his brother, and at other times missions were merely steps across the impassable distance he’d thrown out between the two of them. It was like eating demons, really. Can’t use breaths, can’t become anything other than passable with a sword, but his teeth could tear through just about anything, and you didn’t have to be good at anything except aiming to use a gun. It brought Genya forward, upward, which was really all that he cared about.

 

The world was a cylindrical slash of light seen from the bottom of a pit, of a well. 

 

It was kannazuki, but warm for the season, and the cicadas didn’t seem to know that summer wasn’t over yet either. There was a humid buzz all around him as he crossed through to the other side of the village. The treeline butted up in a darkening mass as the sun finished setting. Genya drew towards it, having heard from the villagers that that was where they’d heard the screams of those gone missing.

 

It was going to be a near-moonless night.

 

The woods smelled of sap and mildew, and turned away from the village lights, Genya’s vision was as adapted as it was going to be to the dark. He hadn’t intended to scout the forest at night, he wasn’t an idiot, but he’d heard from Kocho that his brother was due back for a hashira meeting, and Genya needed to be back at the Ubuyashiki estate in time to catch him. He’d wasted too much time locating this tiny village in the first place, and he wasn’t going to be wasting any more here than he had to.

 

The sun finished setting, and Genya kept walking. He felt nothing amiss, none of the rotting sense of dread that demons gave off like a miasma. There was nothing, then suddenly an aborted gurgle, and Genya smelled blood.

 

“Looks like I did your job for you.”

 

There was nothing to the voice, just the bland politeness of store clerks and station attendants. Genya had his gun in hand and aimed all the same.

 

“Who the fuck are you.” He could make out the form, just barely. Shorter than him, and bulky in the way that layered clothing was bulky. He had picked it out more for the slight movement of it rising from a crouch. Genya didn’t need moonlight to tell him there was a dead demon between them. The blood-smell had gone all ashy, the way demons did when they disintegrated. 

 

“Ah, introductions,” the demon said. “Kamado Tanjiro, nice to meet you.”

 

“You know that’s not what I fucking--”

 

“What about you, demon slayer?”

 

There wasn’t going to be much left of the dead demon if he didn’t hurry, and Genya could already tell he was going to need it. His gun was, as ever, a comfort against his palm. The first shot caught the demon somewhere in the torso, but the second and third didn’t connect, merely echoed uselessly out between the trees. Genya dodged, tucking into a roll in an effort to get himself closer to the corpse. The demon was on him as if he hadn’t moved at all, chill fingers closing around the back of his neck and slamming him into the damp moss and earth. A knee dug in between his shoulder blades, and his gun was ripped from his grip.

 

He’d managed to get close enough, though. The ground his nose was pressed into smelled of blood just as much as dirt, and he opened his mouth to it.

 

The first time he’d ever eaten a demon he’d been beyond desperate. But his world was just narrow enough that the act was nothing more than the next pragmatic step. Eat them before they can eat you. He was less accustomed to the taste of soil, and it took more to swallow it down, but he managed; the demon unintentionally aiding him by pushing his face harder into the earth. It was soaked through with demon blood.

 

He managed to get his knees under himself, to throw the demon. He could see more now, could see the demon staring at him with wide eyes from where it landed.

 

“Did you just--”

 

He didn’t have much time, and struck out, landing a blow where the demon had been a fraction of a second earlier. He could smell it clearer now, a much cleaner scent than he was used to with demons. It smelled faded almost; washed out. It had drawn a sword, but it only deflected his blows when he pressed it with his own. He was much less skilled with a sword, he knows this, but the demon had his gun tucked away somewhere; Genya couldn’t see it but he could smell its metal clearly through the almost-nothing smell of the demon.

 

He was breathing heavy and dawn was a long, long way off. The demon continued to deflect his blows, merely watching him, and Genya felt sick with its obvious interest. 

 

He was probably going to die out here. He wondered, not for the first time, if anyone would tell his brother. If it would mean anything to Sanemi, if anyone did.

 

He’d never be strong like his brother, or Himejima, or any of the other hashira, but his anger had always struck like a blow. He had both height and weight on the demon, and he used it to his advantage. The demon hadn’t made any more offensive moves, so Genya closed the distance between them, heedless, and bore down. The demon’s blade sliced through his left shoulder, and it seemed more surprised about it than Genya. The bite of it was almost nothing, and he could only push himself further, farther, until his own blade cut through the demon’s exposed neck. 

 

His left arm separated from his shoulder with a wet squelch and dangled briefly from his sword before its weight drug his fingers from their grip on the hilt. After that Genya could hear nothing but the blood rushing in his ears and his own frantic heartbeat. He could see the demon’s mouth open in a measured exhale, was close enough to feel the breath against his skin, to feel the breath--

 

He braced himself, strained to pull the blade of his sword clean through. His heartbeat was loud, he couldn't even hear the cicadas any more. The demon locked eyes with him and there was the slightest bit of give, and he thought ah, I’ve done it, I’ve somehow and then there was one hand on his wrist, yanking back, and another steadying the demon’s own head. His sword was gone from his grip, because, he realized belatedly, his right arm was gone too. He tried to kick out, but the demon blocked it, swiped his feet out from under him, and followed him down to the forest floor.

 

The demon pinned his legs with the weight of its own body and leaned down over him, holding his head in place with a strong grip around his chin. He could just barely smell its blood over his own.

 

“You don’t know how to use breaths, do you?” it asked him.

 

Genya couldn't do anything but stare upwards. Like hell was he going to answer it.

 

“I’ve never seen a human do that,” it continued, “eat a demon, I mean. That was really impressive! You managed to cut right through my neck!”

 

It had red eyes, Genya thought, and it was smiling. If it got any closer to him he was going to bite its nose off.

 

“If I drag your arms over here will they reattach?” When Genya just continued to glare it frowned, but it didn't ease off of him. “The effects of that blood you ate aren’t going to last for much longer, are they? Why don’t you tell me your name, and I’ll bring you your arms back? That’s a fair trade, right?”

 

“Fuck you,” Genya felt like baring his teeth like a dog.

 

“Rude,” it said. “We even came out here for the same thing.”

 

“What.”

 

“Killing demons,” it shrugged. “Like I said, doing your job for you, demon slayer. Come on, don’t make me keep calling you that, what’s your name?”

 

“Not telling you shit.”

 

“He was killing the people from that village. That’s why the Corps sent you out here, and that’s why I’m out here too. He crossed a line.” Genya couldn’t fathom what this demon could possibly get out of all this, but it was looking at him hopefully, like it was just a matter of time before it said the right words to get him to talk. He just needed to get it a little closer, he thought. He couldn’t turn his head, because the demon still had him immobile, but he looked away, to the side. Genya licked his lips. They were covered in dirt. 

 

He mouthed his name and the demon smiled. “What’s that?”

 

He whispered it, and the demon relaxed, just a fraction.

 

“Shinazugawa? Like “to not die”? That’s a bit on the nose, isn’t it?” The demon threw its head back a bit when it laughed, but when it turned back to him, smiling, it had moved just the slightest bit closer.

 

It was quick, and jerked back as soon as he made a move, but he managed to get the tip of its nose all the same. He jerked to the side, out from under it, and got his legs up under himself. His right arm was closer, and this demon was powerful, it was so fucking powerful, barely a bite and he could hardly stand it, it was like a flood of fire. He landed next to his arm, twisting to align and it was already threading back to his shoulder. He turned, his arm only partially attached, ready to meet any blow from the demon.

 

It was gone. He could hear the cicadas again.

 

Genya let his right arm reattach then went for the left. He sheathed his sword. The demon had taken his gun with it. Dawn was still a few hours off but he couldn't find the demon anywhere, even with his heightened senses. He trudged back to the village coated in his own dried blood and passed through before any of the villagers could try to thank him for something he didn’t do.

 

++

 

His brother is already gone again when Genya makes it back to the Ubuyashiki estate. He runs into Himejima when he goes to leave, but his master doesn’t have anything to tell him but the usual. His crow comes with orders to head north, so he does. He goes north, and north, and north. He kills a demon on the way, an incidental demon. He keeps going north. 

 

It’s still kannazuki but here it feels it. The trees are all almost bare and Genya has to pull on more layers, to wrap a scarf around his neck. He finally ends up in a little port town and finds the demon he’s been sent after in a storehouse. It’s a kid, it’s a fucking kid, and it nearly kills him because he thinks, just for a moment, that it looks a bit like his youngest brother would have if he’d still been alive.

 

He curls up in a corner of the storehouse after. It smells like sawdust and he keeps breathing in as deep as he can. His wounds have all healed but he stays like that until morning trying to whittle his world back down to just his older brother, just Sanemi. He emerges from the storehouse and the crow tells him he has another mission. He goes where it tells him.

 

++

 

There’s a demon with an art that it uses to turn its skin to stone, its teeth to steel, and Genya has to wait at the Butterfly Estate until a kakushi is free to lead him to the swordsmiths’ village. His sword is little more than a hilt at this point; the demon had caught it in its teeth and bitten it clean in two. It’s his third trip to the village.

 

Kanroji is, as always seems to be the case when Genya comes here, present and already clearly at home. Her yukata is barely doing anything to hold her tits in, and her hair is frizzed with steam from the hot springs. She greets him as she always does, smiling and rising to meet him. Genya ignores her and heads straight for his room. She’ll hound him the entire time he’s here, he knows this from experience.

 

He spends as much time as he can alternating between his room and the hot springs. He trains, meditates. Eats the food he’s given. At the start of his second full day in the village Kanroji sits right next to him at breakfast. There’s grilled fish, and she makes her way through what seems to Genya like an entire lake of them before she inclines her head in his direction. “Are you not hungry, Genya-kun?”

 

Genya realizes in gawking at her he’d stopped eating himself, and scowls when he feels his face heat. He grabs his rice and gets to work finishing everything off as quickly as possible.

 

“Well,” Kanroji adds, “that answers that.” Her laugh is kind, but Genya knows he’s blushing all the more for it. 

 

They eat in silence for a while, before Kanroji at last leans back with a satisfied hum and starts, for no reason Genya can discern, outlining her training regimine for the day. “I know you don’t use breaths, Genya-kun,” she’s saying when he finishes his fish and his name draws his attention, “but I really think we’d both benefit from training with a partner! My sword should be finished by tomorrow, but I don’t like wasting time. What do you think, Genya-kun?”

 

“What.”

 

“Training together! While we wait. It’ll be good practice for both of us, I think.” Kanroji leans forward against the table, elbows resting against it and her chin resting on top of her folded hands. She’s still smiling at him, but it seems small to Genya.

 

He’s really only ever trained with Himejima. Genya knows she’s right, that she has a point, but he’s loath to agree. 

 

“Let’s just try it,” Kanroji says, and her smile seems even smaller. “Just while we wait, okay?”

 

Genya follows her out to the clearing she’d been using in the forest surrounding the village. “I’ve never really seen you fight before, so why don’t we start with some simple sparring? Nothing fancy.” Genya finds himself facing her across the clearing. He nods, draws his sword.

 

Kanroji’s swordsmanship is like nothing he’s ever seen. She’s just as fast and as strong as any demon, and he ends up flung into tree after tree until he manages to get a bead on her, and then it’s all he can do to keep out of range. After only a few minutes he’s sweating, panting for breath. There’s a nervous energy buzzing around him but he can’t direct it anywhere because she’s just too fucking fast, and all the dodging he’s been doing is making it worse. He fucking hates running.

 

“You’re really strong, Genya-kun!” she keeps saying, but what the fuck does that even mean when he can’t land a single blow.

 

“Alright!” she says when he bends over, bracing himself on his knees as he struggles to catch his breath. “I have an idea I’d like to try, if you’re okay with it.”

 

Genya peeks up at her. She’s closer to him than he’d realized, and though most of her is blocked by the fall of his hair, he can still see that she’s more serious than he’s ever seen her. This, more than anything, is what makes him agree.

 

She sits them both down in the center of the clearing. Pine needles prick through his clothing but he ignores it, staring straight ahead at Kanroji as she settles into seiza a bare handspan away from him. “I want to try teaching you breaths,” she says at last.

 

“Breaths.”

 

She holds up a hand, as if Genya was planning on protesting further. He doesn’t feel it's necessary; he’d never thought she was stupid, but it’s laughable that she would--

 

“I know you don’t use them!” she hurries to say. “I don’t mean to teach you techniques, just breathing.” 

 

“I know how to fucking breathe.”

 

Kanroji winces, and Genya tries not to feel bad. “Just, ah, just bear with me a bit? I promise I’m going somewhere with this!”

 

So Genya sits with his eyes closed and matches breaths with her. It’s all fundamentals; the same kinds of exercises he tried with Himejima. He uses some of them for meditation, which is really the only thing he can use them for. They’re at it for hours before he starts to suspect what she’s aiming for. When she changes her breathing he can anticipate it; shifts into a new exercise at the same time or even before she does. 

 

It’s just past midday when she has him stand. They’re both a little shaky from holding seiza for so long, but she has him running sword kata right away, mimicking her. Her forms aren’t like anything he’s practiced before but he’s so in tune with her due to the breathing that he’s soon shifting almost as quickly from one to the next as she is. She uses different breaths for each, and that’s what he tracks, his body moving into each new form she shows him as if he’s practiced them as endlessly as the kata Himejima showed him years ago.

 

When she slows them to a stop she’s beaming at him. “We’re going to spar again now,” she tells him. 

 

Genya feels sluggish at first, the repetitive breathing and kata having drug him into a meditative state out of habit. It takes him a while before he’s able to parry her blows without staggering, and it’s mostly because the longer they spar, the more he can pick out how and when her breathing changes. He’s tiring quickly, still on the defensive more than he prefers, but he knows that if they kept at it long enough he’d be able to predict all of her moves based on her breathing alone.

 

Genya can’t fathom why in hell she’d hand him a weakness like this.

 

She beats him, soundly, but plops down next to him after. He’s laying on the dirt looking up at the forest canopy, and Kanroji hums next to him, a quick soft sound before she leans over him, obscuring his view, and says, “You’re breathing easier, Genya-kun.”

 

He is, is the thing. He’s tired, but not out of breath. He’d been aware he’d been matching her breathing still while they’d been sparring, but hadn’t given a thought to it beyond that.

 

“We should practice again tomorrow before I have to leave,” she says. Genya thinks he should say no, despite what she’s managed to do for him. He can’t help thinking now, what if it’s not impossible, what if I can learn breath techniques, and he hates that she’s made him think that.

 

Instead he says, “Have you ever fought a demon that uses breath techniques?”

 

Kanroji blinks, taken aback, but quickly gathers herself, shaking her head. “No, never. I don’t think I’ve ever even heard of something like that. Why do you ask?”

 

Genya sits up quickly, forcing her to jerk backwards to avoid getting headbutted, and gets to his feet. “No reason, forget I said anything.”

 

“Genya-kun--”

 

“What time tomorrow?” he stops without turning back to her.

 

“Pardon?”

 

“You wanted to spar again. What time?”

 

Genya can feel her smiling at him; can practically hear how pleased she is. “Let’s meet before breakfast! Then we can eat together before I have to leave.”

 

Her sword is finished that night, however, and her crow calls her out and away. When she comes to apologize to him he refuses to open the door.

 

He wakes the next morning and eats by himself. It’s quiet out, save for the birds and the just-waking noises of the village. Genya doesn’t practice Kanroji’s breathing exercises again until long after he’s gotten his sword back. The crow tells him to go south and west, and he does.

 

++

 

When Genya arrives there are three dead demon slayers and the red-eyed demon has a second pinned. With one hand on the demon’s shoulder the red-eyed demon grips its hair with the other and pulls its head right off its body. The demon is screaming, but Genya is barely paying it any attention. The red-eyed demon has a serious look on its face, twisted somewhere between anger and a disapproving disappointment, and Genya’s father had looked like that sometimes, when he was very very young, before it had tipped entirely over to anger.

 

The head comes off trailing the spine like a tail, and the head is begging, Kamado-sama, please, forgive me, I didn’t know, but the red-eyed demon mutters something, too quiet for Genya to make out, and the head is engulfed in flames. It burns to ash, and the body follows after.

 

Sanemi, Genya thinks, Sanemi, and he bends down over the demon slayer closest to him; closes the man’s eyes. He thinks he may have seen the man before, maybe on another mission, or around Ubuyashiki’s estate, but the tap of approaching footsteps draws his attention away.

 

“Shinazugawa.”

 

Genya stares. It’s been months

 

[tfw u start  a fic for a specific pairing and then just want to write “Genya surprisingly manages to get along with the pillars” instead]

 

++

 

Himejima is meditating under the waterfall again. It’s been a while since Genya’s been here, and now on the other side of spring it’s still brisk enough that he somewhat regrets not having put it off longer.

 

“Genya,” his master says, “welcome back.”

 

Genya mutters the answering greeting and starts stripping down to his fundoshi. He leaves his things in a pile next to his master’s and wades out into the still winter-frigid water. He takes his place next to Himejima, the force and chill of the waterfall hitting him with a shock it still takes him too long to shake off. He still has to resort to chanting the nembutsu in order to stand it.

 

“Child,” Himejima says after a while, shifting in the way that means he’s easing out of meditation, “tell me about your last mission.”

 

Genya stares straight ahead, blinking against the water, and tells him.

 

He starts out of order, but Himejima doesn’t call him on it. He begins with the tea shop where he fought the demon. It’d been poisoning the shop’s store of tea and feasting on the weakened customers at night once the poison’d set in. Genya starts with the fight, with his quick victory. He doesn’t say that this surprised him, that he didn’t have to eat part of the demon in order to defeat it. Instead he says that he was able to track its movements, to anticipate its attacks, and trap it in its own superfluous motion. It was a full moon that night, Genya backtracks, and he’d traced the demon to the tea shop right away because he’d been able to feel it.

 

“Oh?”

 

“It’s. Demons are heavier. They make the air heavier.”

 

“I see. Continue.”

 

He’d snuck into the storehouse and tried the tea, eating the leaves dry and confirming his suspicions that it was poisoned. His stomach is strong enough that it had no effect on him. Other than a few cramps, but he doesn’t tell Himejima this either.

 

“It killed around seven of the townspeople before I got to it.”

 

“May those poor souls be reborn into a kinder existence.”

 

He’d left the town before dawn again. The crow hadn’t had a new destination for him, just Himejima’s summons.

 

As Genya trails off, he looks to Himejima, who has moved out from under the waterfall to stand staring back at him. “Your breathing has improved,” he says.

 

Genya hadn’t realized he’d shifted into Kanroji’s exercises. He grunts a confirmation.

 

“I need you for a mission,” Himejima continues. “We’ll be leaving in two days. Come find me when you’re done here, we’ll have supper.”

++



 

Tanjiro has him pinned. Genya pushes against his hold, knowing all the while that he’s going to be unable to break it. Tanjiro is leaning his full weight against him, knees digging into his sides, chest pressed to Genya’s back. “Shush,” Tanjiro whispers, right against the back of Genya’s ear. Genya hadn’t been about to say anything, but maybe Tanjiro had heard it anyway, all the tangled up words gouging away at his insides. “I’ve got you, shh,” he says, pressing the hush right against Genya’s skin.

 

Genya feels over-hot, his fingers curling uselessly against the tatami. He can still taste Tanjiro in his mouth. He feels like he needs to run, to get away, but he can’t. He doesn’t want to. Tanjiro has never looked at him in disgust. Tanjiro’s fingers are gentle where they trail through his hair, scratch lightly at his scalp. “Genya,” Tanjiro breathes against him. Genya feels like crying. He doesn’t know why.

 

Tanjiro moves, settling down completely flush against Genya’s back, his grip loosening enough that Genya knows he could shake free completely if he wanted to. He doesn’t want to. He stays still underneath Tanjiro, inhales the slightly musty smell of the tatami. Exhaling is like giving in. He wants this, what Tanjiro is offering. Genya shuts his eyes as Tanjiro presses his lips first against the shell of Genya’s ear, before moving to the hinge of his jaw, the back of his skull, trailing down all the way to the nape of his neck.

 

Tanjiro opens his mouth enough to press his teeth against Genya’s neck. It should be a threat, but all Genya feels is again Tanjiro’s strength flowing through him, Tanjiro’s strength given freely to become his own. It’s an offer, not a threat. An offer.

 

Tanjiro sinks his teeth in and Genya bites down on his lip to abort the noise he’d started to make. Tanjiro pushes Genya’s hair aside to lap at his skin. His tongue is wet, cooler than Genya thinks it should be. He doesn’t smell blood, and he wishes Tanjiro had broken the skin. It’s stupidly attractive suddenly, this idea of giving back to Tanjiro what he’d taken.

 

“Genya,” Tanjiro says,” say something.”

 

“The hell do you want me to say?”

 

“Anything, just talk to me.”

 

Genya grunts. He exhales loudly against the tatami and then rolls, barely disturbing Tanjiro’s perch at all. He’s surrounded by the flickering yellow-orange of lamplight, smiling down at Genya with the smile that makes him seem nothing more than human. The soft smile, the one that makes Genya feel like more than he is. 

 

“Tanjiro,” he says. 

 

Tanjiro’s smile widens, and he leans down, resettling. His hands, rough and calloused, cup Genya’s face. “Tanjiro,” he says again. He opens his mouth to say something else. He wants to say something profound, like Tanjiro did earlier. He wants to feel Tanjiro’s given name filling his mouth again. Tanjiro kisses him, a chaste kiss, right in the center of his bottom lip. Genya remembers his hands when he shoves them up into Tanjiro’s hair, holding him still so Genya can press back up, unskilled, to seal his mouth to Tanjiro’s. 

 

Tanjiro doesn’t seem to mind. He hums and strokes his thumbs across Genya’s cheeks.