Cataclysm // Demon Slayer Deku

By DgamerV

18.2K 548 194

The world is riddled with evil, stretching far and wide, into the hearts of many. But, Pure evil... unadulter... More

Prologue
I'm Sorry...
The Nobody
Grief
Lowermoon
Reality or Illusion?
Light Hashira
Recovery
Understanding
Grueling Trials
The Gatherings
Intrusive Thoughts
Encounter
The Therapist
A Living Hell
The Prodigy
Unidentifiable
Connectedness
Final Trial
Sickening Trauma
Coming to Terms
Emerald
Stendhal
The Artist
AFO
Dragon of Hokkaido
Demon King
Eraserhead
Corruption
The Sample
Spider's Web
Winding Ribbons
Puppeteer
Blood Hashira
The Two Kings' Nightmares
Night to Remember Pt. 1
Night to Remember Pt. 2
Interrogation
Trustworthy Pt. 1
Trustworthy Pt. 2
Trustworthy Pt. 3
The Lesson
Demon Hashira
85%
Boiling Point
A Ruler Cannot Be Ruled
Multiplicity
Rampage
Lowers
Ruins
Heroism
Ensnared
Radiance
Jackpot
Focused
Hellfire
Light in the Darkness
Marked
Skyfall
Condemned Are The Wicked
Omni-Hashira
Devastation
Epilogue
A/N: Information

Breath of Life, Pain of the Soul

83 6 0
By DgamerV

Kagaya's POV:

I maintained a small smile as I walked along the path through the DS Corps graveyard, filled with fallen warriors of centuries past. The humming of birds in the sky acted to calm myself down slightly.

The caring warmth of the rays of sunlight quickly transformed into a scorching heat, filled with malice the deeper I walked through the graveyard.

My mind already had all the answers, fully prepared for what or who I'd meet not too far along the concrete pathway. 

The only regret I felt at the moment was that the one who would bring my life to an end made himself known far too soon.

"So you're the Master," a voice spoke up from not too far in front of me.

My gaze fell on a young man who was crouched down in front of a tombstone, his piercing red eyes glued onto it. "So this is how it happens, Gushiken?" I muttered underneath my breath.

"This is him," I thought to myself. "The demon king. Tanjiro Kamado."

He rose to his feet, head turned in my direction, gaze stilling onto me.

My smile dropped, eyes narrowing as I rested my right hand on the hilt of my katana, taking several steps back in preparation for an attack.

Tanjiro Kamado only stared at me, arms crossed, what seemed to be—

"A katana?" I thought, incredulously.

I frowned. The sun was still out, glowing with an intense heat. And yet...

"So Yushiro-San was correct," I thought to myself, slowly unsheathing my blade. "He truly is unaffected by sunlight."

"That would mean that my blade is meaningless."

"How did you find this place?" I questioned the seemingly immortal demon king, making sure to keep my distance.

He blinked once, gaze narrowing.

"We'd be here for a while if I were to go into everything I had to do in order to narrow down on this location," Kamado responded. "It's been several centuries since I've personally attacked a demon slayer location. Never have I found one that housed the Ubuyashiki family."

"And I suppose that is why you're here. To kill me? To destroy my family?" I inquired, raising my katana slightly up higher. "Was using Dragon to wreak havoc on Tokyo a part of your plan to dwindle our numbers before coming here yourself?"

The demon king had the audacity to seem upset at the accusation, crossing his arms in front of his chest as he did so.

"Not at all. What the previous Lower 1 did was entirely out of my control. I had no part in what happened that day. However, I do admit that what he did was effective in harming the DS Corps as a whole," he responded.

I narrowed my gaze at the demon king, the most powerful creature to have ever existed, the unfortunate pinnacle of strength.

"Yet you decide to confront me where so many of my children have been buried and laid to rest. Do you wish to undermine their sacrifices? Disrespect their gravestones? If so, I'll do everything in my power into preventing that from happening."

Tanjiro shook his head. "I simply wanted to see what you've lost, see how many have been lost on your side. I watched as Dragon faded away into nothingness, and believe me when I say that I'm glad he has been taken care of. He was nothing more than a nuisance."

We both stood quite for a few moments, neither of us making even the slightest sound. I was the one to finally break the loud silence.

"A nuisance? If he was truly a nuisance, surely you would've dealt with him long ago," I commented, not buying into the demon king's supposed dislike for Dragon. 

"He has been an effective tool for years, incredibly powerful, so I continuously held off on dealing with him myself. I was planning on doing so before his son beat me to it."

"I see."

That's all that I managed out, before dashing straight for the demon king, swinging my sword swiftly, aimed for his neck.

He didn't move from his spot, standing perfectly still as I slammed the sharp edge of my blade against the side of his neck.

I stared into his slightly narrowed eyes with my slightly wide ones. I had known it wouldn't have been enough... but...

I averted my gaze to the single drop of blood that slowly dripped down from the paper cut-like gash that my blade left in his neck. I watched as the demon king opened his mouth as if to say something, ready to mock or belittle my attempts at injuring him, but that never came.

Instead, all that came next was a slight inhale of breath, followed my a small crackling noise that slowly exploded into one of thunderous booms, an intense ball of energy forming just in front of his mouth.

My eyes widened, leaping back as fast as I could, narrowly avoiding the point-blank shockwave blast.

The immense amount of energy oozing from that blast was incredible, far greater than anything I had ever encountered in the past.

I looked at the ground surrounding the demon king, concrete walkway cracked, large chunks having been slightly uprooted by the attack, a large crater in the ground where the attack landed.

I watched in bated breath as several long, thin, red tendrils sprouted out from his back, tipped with seemingly sharp points, each one positioning around Tanjiro Kamado's body. I rose to a higher stance, positioning my blade in front of my chest.

The red tendrils crackled with intense sparks of flame, instantly igniting like a wildfire, each tendril shooting at more at immense, nearly imperceptible speeds.

I took in a sharp breath, bending my body backwards, narrowly avoiding the first tendril whip. Immediately after, I jumped up a mature or so into the air, avoiding yet another whip-like attack that had been aimed for my legs, only for another tendril to shoot out straight for my chest.

"Life Breathing: First Form: Serene Defenses."

I sliced my katana through the air, carefully and precisely deflecting each and every attack sent my way, before my feet made contact with the ground. Exhaling, I gracefully landed on the ground, leaping to the right as another tendril shot out like a whip, uprooting a large chunk of the concrete pathway.

I adjusted the grip on my katana, focusing more of my strength into my legs as I dashed forward, swinging the blade in a downwards arc, katana glowing a faint yellow as it struck Tanjiro's arm, managing to leave a deep gash. However, it wasn't enough to fully slice it off.

Tanjiro clenched his fist, swinging his other arm around as sparks of flames crackled from his knuckles. I managed to dodge just in time, but the flames instantly leapt forward as if they had minds of their own.

Nothing caught fire, but with the amount of greenery in the area, anything could catch fire at any time if this kept up.

"Life Breathing: Second Form: Phantom Cleave."

In a single motion, I brought my blade down, across the demon king's chest, expelling enough force through my strike to send him staggering a good meter back.

"It's been set in stone. This will be my end, but if so, I will ensure that I damage the demon king as best as I can."

<•------------•>

DKT's POV:

Digging my feet into the pavement, I came to a quick, abrupt stop, an unnatural feeling welling up within me, as if I had just been hit by a semi-truck. No. Even that wouldn't be enough to describe what that strike felt like.

My breath hitched for a moment, arms shook a single time from the man's strike, legs firmly anchoring me down.

"What was that?" I asked aloud, looking down at my chest. I received no physical injury from the strike, even if I had it would have healed instantly. Even so, this feeling... a feeling that I could only assume to be pain  was still present throughout my body.

I looked up at the him, narrowing my eyes as I straightened myself up. "What was that?" I repeated with a far more demanding tone.

Ubuyashiki didn't respond, instead wasting no time to perform another strike, one that I didn't allow to land. I leapt back with urgency, avoiding the sharp edge of the blade, again and again and again.

From that single strike, I felt slightly slower, slightly weaker, but incredibly more on edge.

I jumped up, above Ubuyashiki, wrapping my fingers around my sheathed katana's hilt, pulling it out of its position and slicing it through the air, aiming the katana's edge for the man's neck.

Ubuyashiki managed to block my katana with his own just in time, however, the force behind my strike was enough to send him flying several meters back, nearly crashing into a tombstone.

I adjusted my grip on my katana, bending my knees slightly in a fighting stance.

It's rare for anyone to make me use my katana as I can usually kill anyone with my physical strength alone. However, whatever that attack was, was more than enough to make me understand that this man's strength and capabilities were not to be taken lightly. 

I dashed forward, not letting up, immediately swinging for the man's neck, but yet again, it was blocked just in time. However, the man's blade was a bit nicked from the collision.

The pain caused from before continued to linger and spiked with each action I made, like a leech that constantly drained me of my energy.

It wasn't something I could simply ignore. It was admittedly concerning.

"Life Breathing: Sixth Form: Vengeful Grief."

Ubuyashiki dashed towards me, thrusting his katana forward at immense speeds, a strong rippling effect tearing through the air.

I managed to dodge the brunt of the attack, however, it barely managed to leave a small cut on my forearm.

Usually, I wouldn't even spare a second of thought at the insignificant injury, but, that same pain, that same strange feeling of dread overcame my entire body all at once. 

The cut took slightly longer than it should've to heal.

I ducked under another slash, countering with my own, dragging my blade through Ubuyashiki's side, leaving a massive, fatal gash that spilled blood. I averted my gaze up to the man's face, expression clearly suppressing the pain he was feeling.

He reversed his grip on his katana, jabbing the blade into the back of my neck, only to violently drag it out, cutting off a chunk of flesh.

My left eye twitched, that same strange pain shooting out throughout my entire body once again. I narrowed my eyes as I moved behind the man, feinting an attack, drawing an attempted counter from the man before I moved slightly in front of him, landing another fatal blow across his chest.

Ubuyashiki sucked in a breath, swinging his blade perpetually, each slash precisely aimed for the most unguarded parts of my body. It wasn't difficult to see right through this, and thanks to 'that world', I could see through his every movement.

Blood continued to spill from his injuries, the gash on his side not quite deep enough that his intestine began to hang out from the injury. And yet, he continued to attack, continued to fight, despite the fact he must've known that this would end in his death.

"Life Breathing: Seventh Form: Pain of the Soul!"

I frowned, preemptively positioning my blade in front of my chest in preparation for something powerful. However, no amount of preparation would've prepared me for the very nature of the attack.

Ubuyashiki performed a flurry of slashes, each one aimed for my joints. That on its own wasn't too concerning, considering the fact that I managed to deflect each and every one of the strikes. No. What made this technique truly concerning was...

I sucked in a sharp breath, something deep, deep down screaming out in pain and discomfort, entire body shaking with the force of the strikes. It seemingly didn't matter that I blocked each strike, the force and effects of the attack were both still wildly successful.

I tightened my grip on my katana as my back slammed against the base of a tree, nearly uprooting it from the ground.

Cough

My eyes widened in disbelief, a bit of blood flying out of my mouth. "Did I just—"

I whipped my head to the side, narrowly avoiding a piercing jab from Ubuyashiki's blade just in time.

The corners of my mouth twitched slightly, eyes narrowing as I met the man's determined, seemingly unbreakable gaze.

"So that's how you're doing this, Ubuyashiki," I said, bashing the man's head in with the butt of my katana, garnering a resounding crack. "It must be your quirk, yes?" " I questioned, watching as he staggered back in pain.

I controlled my spine whips that hung from my back, shooting all of them at the man, fully ready to slice him up into as many pieces as I could. 

"Life Breathing: First Form: Serene Defenses!"

Crack

One of the spine whips snapped a nearby tree in half, the tree nearly toppling over on top og Ubuyashiki, but he managed to evade.

"That quirk of his doesn't seem to be injuring my body directly. Instead, it's harming something else, completely," I thought to myself, dodging to the side, avoiding a powerful projectile slash. "Harming something completely unprotected by my regeneration."

I took a sharp inhale of breath, building up a concentrated ball of energy, but it was swiftly interrupted by a counter attack, destroying the ball of energy before it left me.

"His quirk shakes the very soul."

I leapt to the side, avoiding yet another strike, the force of said strike being enough to destroy a tree that got in its way.

I narrowed my eyes, confusion internally taking over.

My gaze fell on Ubuyashiki's neck, a strange orange formation fading into existence, resembling a phoenix.

"That wasn't there before," I thought to myself, swiftly noticing the change in speed and power behind his swings.

The rapid beats of the man's heart was something that I couldn't ignore. A heart beat that fast would kill most humans, and yet, it seems indicative of this new found boost in energy and strength.

Deep down inside, I felt as though I knew what this meant. I simply couldn't put my finger on it, as if the part of my mind that knew had been blocked off from the rest of my mind.

I continued to focus more on defense and evasion rather than offense. I can't allow this man to land another strike on my body. He's more skilled than I expected. If I allow this to continue, backup may arrive, which will only make this more troublesome for me.

I need to dismantle the Ubuyashiki family. Once I do so, the rest of the DS Corps will begin to collapse. 

<•------------•>

Kagaya's POV:

"Life Breathing: Second Form: Phantom Cleave!"

The demon king narrowly dodged my strike, but he didn't attempt to make a counter. In fact, most of his concentration seemed to be focused on evasion rather than actually fighting back, as if he were waiting for the perfect time to strike. 

Yes, that's exactly what he was doing.

He likely understands what my quirk can do after being affected by it several times already.

I narrowed my gaze as I narrowly dodged a slash from his own katana, seemingly made of pure metal instead of flesh, like most demonic weapons.

Blood continued to drip from my mouth as I continued to fight, completely ignoring my rapidly worsening injuries. 

"Life Breathing: Sixth Form: Vengeful Grief!"

I dashed forward once again, putting all of my strength into a lethal jab attack, only to narrowly miss the demon king's neck, creating a shockwave that rippled through the air.

"Sun Breathing."

My eyes widened in shock and fear, an instant sense of preservation spawning within my body and within my mind. 

"Sun Breathing?" I thought to myself. "As in...—"

"First Form: Dance!"

The attack was simple, yet swift and precise. The demon king sliced downwards, creating a large, painful gash that ran from my midsection down to my stomach, the gash itself stinging with a burning sensation.

The gash wasn't deep enough for any of my organs to spill out, but it was deep enough that the newfound energy and strength in my body decreased greatly, from that one, simple attack.

I coughed up a river of blood, unable to dodge his follow up attack. As a result, I was sent flying, crashing into another tree, blood tainting the beautiful greenery and floral life.

This place was surrounded with wisteria trees and flowers, more than enough to affect most demons. And yet, the demon king was completely unbothered. 

My entire body shook with pain as blood only continued to spill from my wounds. 

"Life Breathing: First Form: Serene Defenses!"

I deflected most of the demon king's spine whips, however, one managed to break through my defense, violently slamming into my side, sending me flying several meters to the left.

Each breath I took felt like a battle, a battle for survival. The adrenaline acted to conceal some of the pain that I was feeling. However, the demon king's strikes are far too powerful for mere adrenaline to mask the pain of.

Luckily, not a single tombstone was destroyed as we both left the graveyard to continue our fight  in the tree line.

"Sun Breathing: First Form, Modified: Dancing Flash!"

A slight crackling sound, resembling electricity, rang through the air as the demon king blitzed towards me at incredible speeds, flames surrounding his arms and his blade.

He moved far faster than the blink of an eye, his blade moving like a missile towards my neck.

As fast as I could, I brought my own blade between his and my neck, just barely managing to avoid being outright decapitated.

However, it wasn't enough to conflict with the force behind the demon king's attack.

Crack

My eyes widened as I was sent flying back at high speeds, katana snapping at the base as my body crashed through several trees, several loud and painful cracking sounds echoing from my back.

By the time I finally came to a violent stop on the grassy ground, I couldn't move. I could barely moved my arms, but I couldn't move my legs at all.

I was barely able to push myself onto my side, vomiting up blood and bile.

Cough

Cough

My chest heaved up and down, breath quickly becoming sporadic, arms shaking as I struggled to prevent myself from falling back flat on my back.

My vision began to blur, ears beginning to ring, memory after memory after memory replaying themselves through my mind like a film.

I slowly, and shakily turned my head, averting my gaze to the demon king who stood over me, expression blank, but his eyes screamed pity. 

<•------------•>

Izuku's POV:

Caw

Caw

Emergency! Emergency!

The master is battling against the demon king! He is unaffected by sunlight as well as the wisteria!

You must rescue the master!

Hurry! Hurry!

"No no no no... This can't be happening!"

The light breeze swept through my hair as I ran, ran as fast as I could, katana already out of its sheath, firmly held in my right hand, while my left hand gathered as many anti-demon bombs as it could.

My chest heaved as I tried my very best to steady my breathing, rushing past countless trees, steadily approaching closer and closer to the graveyard.

"It's the middle of the day... how is this possible?" I thought to myself

I tuned out everything and everyone else. The only thing on my mind was getting to Master as fast as I possibly could. I shook my head hard, swallowing deeply, teeth clenched together, eyes slightly squinted together.

I still wasn't fully healed from my injuries. The pain was still present, and running this fast already only acted to worsen the pain.

But I didn't care. Not in the slightest. Master's done so much for me, for all of the Hashira, and I wasn't about to allow him to die. Not to the demon king.

From the corner of my eye, I watched as Agatsuma-San disappeared into a puff of playing cards, followed by Gyutaro-San, then Takeshi, and so on, each one being surrounded by Genki's playing cards only to disappear as soon as the cards disperse.

I turned my head to Genki. Neither of us said anything as he surrounded the both of us in playing cards.

<•------------•>

DKT's POV:

I kept my gaze on the phoenix mark on Ubuyashiki's neck, watching as it slowly began to fade away. As soon as it did, I met the man's gaze, a quick flash of pity spawning in my mind, before I quickly snuffed it out.

My body still ached with a slight lingering of pain, soul having truly been affected by Ubuyashiki's attacks.

He was impressive, incredibly impressive. The strongest demon slayer I had ever encountered in my five hundred years of being the demon king.

"I see you have no more fight left, Ubuyashiki," I said, keeping my blade by my side, gazing into the man's very soul.

I didn't feel the slightest sense of malice, anger, hatred, or fear from the man. Even on the verge of death, he remains calm. He must know that he'll die here.

He smiled up at me, a calm, genuine smile.

"No more fight left?" Ubuyashiki repeated my own words, chuckling softly to myself, blood droplets flying out of his mouth as he did so. "I suppose you're correct."

I blinked a single time, body filled with a strange kind of warmth. "What is this feeling? I thought that killing this man would satiate the strange desires in my mind, but they haven't gone away."

"You'll die here. You've failed to do anything of value, and for that, I pity you, Ubuyashiki," I stated, beginning to raise my katana up.

"I've failed? Perhaps. Perhaps I've failed to harm you directly," Ubuyashiki agreed, nodding his head as he did. "But I haven't failed in what I've managed to build up. The DS Corps and its Hashira will stop at nothing to eradicate all demons from this world. It doesn't matter if I die. They will continue to fight without me."

I narrowed my eyes at the proclamation, pausing for a moment before finally deciding to respond.

"That's an impossible goal, Ubuyashiki. You know that. I can't die. So many have tried and failed.  Decapitation, sunlight, wisteria. No matter what you demon slayers try, you cannot defeat me. You can't kill me."

Ubuyashiki coughed up some more blood.

"And yet, for the first time in your life, you felt pain," he accused, smile widening slightly, eyes gleaming with an intense glare. "I made you feel pain. Instead of attacking your body, I attacked your very soul. I'm sure you've figured that out already."

I frowned. "And now you'll die. That method won't be used against me again."

The man's smile didn't waver, falling into one of calm.

"I'll allow you to believe that, Tanjiro Kamado."

I raised an eyebrow before nodding my head in understanding.

"Your son has the same quirk, doesn't he? Or... a similar one. Once I kill you, I'll make sure to deal with him and then I'll deal with the Hashira," I threatened.

But even then, the man's smile didn't falter as he raised a shaky arm up, palm outstretched, coughing up more and more blood.

An intense feeling of malice and bloodlust began to ooze from Ubuyashiki, something I hadn't considered possible after witnessing his calm and serene nature.

"Is he—"

I quickly sheathed my blade, an intense glow of light exploding outwards from the palm of Ubuyashiki's hand.

But it was too late.

Boom

I couldn't dodge in time, as I was struck head-on by what I could only assume to be Ubuyashiki's last resort.

"In the end, we will win."

That was the final thing that came out of Ubuyashiki's mouth, before the intense blast of light came to a violent end.

<•------------•>

Author's Note: The demon king has defeated the head of the DS Corps with minimal effort. However, in consideration of Ubuyashiki's soul attack as well as that final explosion of light, what will the long term consequences before for Tanjiro Kamado? Will he simply shrug it off, or will his soul be irreparably damaged?

2 chapters left. 


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