Chapter Text
Where am I?
The only thing you could see was a murky black sky.
Then it hit.
The pain.
The burning, dull pain. Bubbling through you, distorting your vision, spotting your field of sight with flickers of red.
Then all of a sudden, your senses came reeling back at full force, and it was as if you were thrown right in the path of a lumbering train. You wanted to gasp for air, but the only thing coming out your mouth was blood.
Warm. Sticky. For a moment, it did not feel like it was you who was heaving up blood, but someone else.
You quickly shifted over to your side, and the rest of the blood that had been stuck in your throat came gushing out in a dark red waterfall.
"[Y/n]-san!" "Onee-chan!" "QUIET WEIRDO!"
"[Y/N]!!!"
Ah, now that brought you back. Especially that thunderous bellow.
You wiped the blood from your face, then staggered to your feet.
Though still a bit unfocused, your eyes could at least take in and truly register the situation at hand now.
The mop of pink, the deadly laceration of dark marks. The flash of gold and crimson. Glimpses of the panicked trio.
You remembered now.
You were sent on a joint mission, with Rengoku Kyojuro, Kamado Tanjiro, Agatsuma Zenitsu, and Hashibira Inosuke, on the Mugen Train, to get rid of a demon that had devoured over 40 people in a relatively short period of time. You'd fallen into a dream, much like everyone else, but the only difference was that you'd woken yourself up even before Tanjiro could.
Everything in the dream you'd been pulled under was a fabrication. You knew it very well.
Too well, in fact.
All you needed was a single word from your lips, and you had awoken.
Just like that.
But of course, life as a demon slayer could never be as simple as that.
As soon as the train-infused-demon was obliterated, a new problem had shown up.
Akaza.
Upper Moon Three, one of the toughest opponents any of you had ever faced.
The battle had been, and was still, ugly. The demon had been able to counter every attack Kyojuro had thrown out, and even managed to break a few of his bones. You and the boys had been strictly commanded to stay on the sidelines, but apparently you weren't one to stick to orders for too long.
Just a few minutes ago, Akaza had approached with a deadly hit that could have blasted Kyojuro through an entire train car.
And it was right then that you'd intervened.
Again, it'd just been a simple, single word. A command, to be accurate. One that transferred the impact of the hit onto you instead of Kyojuro.
Hence why you were only able to get back to your feet just now.
"[Y/N]!" Kyojuro bellowed again. His eyes were burning, even brighter than the fire from his blade, but the heat in his eyes held more shock and fear than anger. "Just what do you think you are doing?!"
You took a shaky, deep breath.
You couldn't let Rengoku Kyojuro die.
Being a kotodama meant you couldn't waste your breath. Every word you issued had to be planned. Precise. Had to change the course of a battle with the least effort.
But Upper Moons were an exception, it seemed.
You wagered the best course of action was to delay this all the way until the break of dawn. A glance at the sky told you you only needed to hold on for less than half an hour.
You could do this, you thought.
You wouldn't let Rengoku Kyojuro die.
You took a step forward.
"Stay back!" Kyojuro shouted.
You wanted to laugh, but decided not to stir your already angry organs. Kotodamas were always the one to issue commands, not the other way round.
"Oh, this is getting interesting," Akaza's voice took on a bit of a lilt. "You don't seem strong, though. Or was my compass wrong?"
You ignored him. Every step you took felt like your legs were made of lead, but you didn't stop. Even as Kyojuro turned more and more aghast the closer you got.
You looked straight into Kyojuro's eyes.
Then you uttered the longest sentence you'd ever said.
"We fight together."
Your voice was nothing more than a whisper, but Kyojuro still caught every word.
And even though there was still fear—fear that you would die, fear that he wouldn't be able to protect you—Kyojuro saw the determination in your eyes, a willpower that mirrored his own.
He took a deep breath. "Very well."
"This is going to be so, so, fascinating." Akaza's icy jeer cut in. "I don't eat women, but I'm not against fighting one. Especially someone like you. You don't use breathing techniques, do you? Maybe—"
"Lightning; fall."
A purple chasm of lightning divided the clear night sky into two clean halves. Without missing its mark, it struck Akaza on the arms.
The demon leapt back with a pained roar, his forearms left where he was just standing seconds ago as they sizzled with a burnt stench. "What was that?!"
You didn't even pause to catch your breath.
"Fire; rise."
Instantly, fire emerged from the barren ground, trapping Akaza in a flaming circle. The demon shrieked in agony as the fire burned and marred his skin.
"Lightning."
Another jab of lightning, straight for his head. Akaza remained nimble enough to avoid the attack, though at the expense of an eye that had caught fire.
And instantly, Kyojuro saw and understood the opening you'd created.
"Breath of Flames, First Form: Shiranui!"
A line of fire came forth from his blade as he trained his target straight for the demon's neck. He barely had time to register the fact that the fire you had summoned was actually warm and welcoming to him before his blade buried itself into the demon's skin.
Still, Akaza was too strong. He'd managed to deter Kyojuro's hit with a regenerated forearm, while his other newly grown hand had already curled into a fist. With the way it was going, that arm was most definitely going to pierce straight through Kyojuro's chest.
The trio's screams echoed, only dully, like they were coming from somewhere far, far away.
Your body had moved even before your mind could finish the thought.
"Shield."
An invisible wall sprang into existence just mere inches from Kyojuro's chest, meeting Akaza's blow head-on, then sent the demon flying backwards with the collision.
At the same time, you let loose yet another rush of blood from your mouth as you dropped to one knee.
"[Y/N]!!!"
You lifted a hand to signal that you were all right. You could palpably sense Kyojuro's eyes, burning, like two flaming torches, boring straight into you.
This was the price of being a kotodama.
Every word you spoke inevitably became a command, but in return, it would chip away the very essence of your life force. You'd lived with that deal, etched into your bones, for as long as you could remember. Of course, generally it wouldn't do too much damage, as other missions didn't require much use of your abilities.
Yet in order to keep the fight against an Upper Moon going until sunrise, you had no choice but to call upon the extremes of your powers. Again. Again. And again.
And the accumulated effects had cost you. Dearly.
Your throat felt like it was burning. And the life—you could feel it seeping out of your body, weakening your support, slowing your movements.
No. You shook your head. You had to remain on your feet.
Your boots scraped on the ground, a bit keenly, as your staggering legs fought to keep your stance.
"[Y/n]! Are you all right?! You shouldn't—"
"Focus."
And with great timing.
Apparently the rebound of the demon's own attack hadn't kept him down for long. Already you could see the mop of pink there, reappearing at the edge of the forest, almost glowing with an eerie sheen.
And his eyes: those cursed eyes, scarred with the demon's rank, were tainted with fury. Fury at being interrupted at the last minute, when he was so close to getting his prey.
"You..." Akaza seethed.
Kyojuro shifted to shield you from Akaza's view, but you stopped him with a hand on his shoulder.
"His target is me." You rasped, the foul, metallic tang of blood a cacophony on every fiber of your vocal cords. "I'll be the bait, you deliver the final blow."
"But—"
"Obey." You shut Kyojuro's protests down. Even though you could see the indignance flaring briefly in his eyes, he had no choice but to do as you said.
A ripple in the air—Akaza was reactivating his compass.
You trained your gaze, razor sharp, on the demon. The familiar reddish-blue snowflake was beginning to unfold.
Unceremoniously, you shoved Kyojuro out of the way, just in time for the demon to growl its attack.
"Blood Demon Art: Destructive Death!"
"Lightning. Fire. Dance of Hell!"
Ice, lightning, and fire crashed together in a beautiful, yet terrifying, tapestry of sounds and visuals.
And power.
Kyojuro could feel all the hairs on the back of his neck stand on end. It had been a long time since he'd felt anything close to this.
The sheer power, rolling off of you, erupting from the sky and the ground, trapping the demon in a cage.
The demon roared in agony. The lightning, the fire—all of it, everything was too much. He could sense the entire layer that was his skin peeling away, crumbling into nothing but fine dust, the aftermath painful and bloody. He felt like he was in Hell, even though he had yet to set foot there. Every tiny prick of your spell was corroding him, through the flesh, through the bone. Reflexive regeneration was still at work, but for the first time in centuries, he felt fear. Panic. Incompetence, even as a demon.
He was regenerating too slowly.
Not even Muzan's punishments could compare to a fraction of this.
Now.
It was an unspoken understanding between the two of you.
At that precise point, Kyojuro's breathing technique reached its peak.
"Breath of Fire, Ninth Form: Rengoku!"
The roar of a dragon, made of purest fire, rose above the clamor, thunderous as it plunged down, straight for the demon caught in the middle of it all.
Kyojuro's blade hit its mark: sinking inches deep into the demon's neck, leaving nothing between the demon's head and the rest of its body but a hair's breadth of demon flesh.
Almost there. Almost there!
"Lightning: excruciate!" You quickly made up for the gap.
The demon shrieked.
Kyojuro's glowing katana went in a little deeper.
He grit his teeth. He could feel the blood seeping from his own mouth, could feel the blood vessels in his eyes fit to burst from the extreme physical strain.
But he couldn't stop. Not here, not now, when you were so close.
He tightened his grip on his sword. Summoning every ounce of strength he had left, he unleashed it all in a powerful roar, and forced his arms to swing all the way through, with all his might.
And then you all heard it: the sickening sound of blade slicing cleanly through flesh.
The sheer will and force you'd all channeled into this final blow had you all reeling.
In an instant, all color, light, and sound vanished. Something snapped within you, and you suddenly went slack—signs you had been pushed way past the limit.
You felt like you were underwater. Everything came so clearly, yet so slowly, and so far, far away.
But the most penetrating sensation was the cold.
You felt so cold. It was as if ice had seeped into every fiber of your being.
Akaza's head. Falling, rolling on the ground. And the eyes—fixing you with so much hatred, so much...pain. Kyojuro's shouts. You couldn't hear much, but it sounded like he was calling out for you. The three young boys, who'd been stunned silent all this time, seemed like they'd just managed to find their voices again.
Why isn't the demon dead yet?
Your teeth were chattering together. And the fatigue—the strength was leaking from your fingertips, even faster than you could draw a breath.
With an angry kick, Kyojuro sent the demon's head flying out a good yard away. He knew Upper Moons had the ability to regrow even their heads, but now that the head was a good distance away from the body, he figured it would have to take some time for Akaza to find his head, let alone regenerate.
"[Y/N]!" He ran towards you. He sounded alarmed. Panicked. He could see hints of frost in every exhale you made.
The first streaks of sunlight filtered through the once dark clouds.
Never had you known sunrise to be this beautiful. This warm.
You did it.
We did it, you wanted to say. I'm fine, you wanted to say.
But instead, the world spun, and darkness snatched you away.