'The air sure is thin up here, huh?'
A week.
It's been a week of training.
'Astronomical progress'
The cold air rushed past me as I clenched my fist. My eyes became clear as I witnessed the muscles and bones of my body.
Replicating the Martial Arts was...admittedly not that hard. With the See Through World I could accurately see which muscles would move in one stance. After that, it was just a matter of forcing my own muscles to move the same way.
'Of course, copying and using them is different.'
There's no problem slowly going through stances in a relaxed, safe environment.
A fight though...
Let's put it this way, you've done Maths before,e right?
When you first open a maths book, you see a bunch of formulae and some other text explaining the concept of the book.
'I don't know much about that, though, I always skipped the explanation section.'
You know the quadratic formula, right? You see it in a textbook, plug it into a simple equation—bam, solution in a few lines. Feels easy.
Then they throw fucking PHD level questions in.
One of those multi-layered nightmares where you need to differentiate, apply some obscure trick, rearrange a bunch of nonsense, and then, finally, you get to a point where the quadratic formula actually comes in.
That same formula you thought you mastered? It's still there. It still solves the problem. But getting to the point where you can use it? That's the hard part.
Fighting's just like that.
Learning a stance and using a stance are different things.
Fighting someone—especially demons—is an extremely delicate process. You're not just swinging your fists around, every move has to be calculated.
You need to calculate the offensive of the demon and plan whether you have to counter-attack or defend, and even after that, you have to plan further ahead on how you're supposed to counter-attack in a way that will give you a long-term advantage.
And even if you figure it all out, you still have to take in variable factors.
Are there any civilians around who could get hurt? Can the Demon use a Blood Demon Art?
Most skilled fighters can do this because they're using a style they've honed over years. It's muscle memory. Instinct. They don't think about their next move—they just do it. Only by reaching this level of mastery can you properly plan a fight.
So naturally, using a brand new technique that works completely different from your traditional techniques in a fight is not the brightest idea.
'Which is why...
My eyes narrowed as my face broke into a small smile.
...I have jumped off this mountain'
You read that correctly.
Currently, I, Aoyama Yuito Daichi, am in the middle of falling off the peak of a mountain headfirst.
The cold, merciless wind whipped against my face, so sharp and fast it felt like needles slicing my skin. My eyes stung just trying to stay open, and the ground below was rushing up like it had a personal grudge against me.
So, how is it that I am still thinking? Shouldn't I have already hit the ground and turned into splattered meat already? No, wait, why am I falling off a mountain in the first place?
I'll answer the last question later, as for the first two...
As I said before, the combination of breathing techniques with martial arts provides various benefits. The collaboration of Water Breathing with Martial Arts increases mental and cognitive functions.
In other words, I'm thinking so fast that it looks like time has slowed down.
'Since my mind is working overtime and this technique functions off of Water Breathing, I'll call it...Overflow'
...
'No wait, that's a Hentai. Then, I'll call it Overcharge'
Still falling, by the way.
'Hm, let's see. Judging from this distance, I'll hit the ground in around 10 seconds, or about 30 seconds in Overcharge time.'
Time to lock in then.
Suddenly the wild air rushing through me stilled for a moment as if somehow the wind itself sensed a change in the man who dared to go against nature itself.
And then-
*sssss*
A hiss escaped my lips as steam curled out with every exhale, my breath burning against the frigid air like smoke off molten steel.
My lungs inhaled like crazy, eventually becoming ballooned with air, greedy and desperate, Making my heart beat at extreme speeds, as if it was roaring—each beat a war drum—as blood surged through my veins like a raging river.
Every muscle screamed as they swelled and bulged, overflowing with oxygen-rich fuel, primed for impact.My muscles pulsed and flared, fibers twisting and bulging under skin that could barely contain them.
"Martial Union-"
The moment I even thought of activating the technique, my body snapped into action.
I could see it—feel it—down to the smallest twitch. My entire frame tightened like a coiled spring, the muscles locking around my bones with terrifying precision. My bones themselves seemed to compress, compacting ever so slightly, reinforcing themselves under the sheer tension flooding my body.
"-Water Breathing-"
With gritted teeth, I forced an overwhelming surge of blood into my legs. The moment it hit, my muscles expanded violently, tightening to a point where the fibers strained, pulling against their own limits. I could feel the faint tearing, a sharp reminder of just how much pressure my body was under.
'Young Aoyama... I cannot allow you to do this.'
Gyomei-sensei stood before me —tall, immovable, like a shrine carved into the mountains themselves. His massive hands were clasped tightly in prayer, the beads wrapped around his fingers trembling ever so slightly. He wasn't angry. No, this was something deeper.
Fear.
'Your method is too dangerous,' he said, his voice thick with grief. 'If it doesn't work, then you will die.'
"Tell me, Sensei…" I whispered back, shoulders tense and fists clenched at my sides, 'Don't we Demon Slayers already gamble our lives with every breath we take?'
...
There was silence—long, heavy, aching.
It wasn't the silence of hesitation. It was the silence of heartbreak.
'Aoyama...' he finally said, and in his voice I heard the cracks of old wounds trying to stay sealed, 'I don't think I'll be able to handle losing another child.'
That was unfair.
But my resolve isn't so easily broken
'Don't worry Sensei, even if my technique fails to work...
I turned towards him, a re-assuring smile on my face
'Then I'll force it to work-
"THEN I'LL FORCE IT TO WORK-
EIGHT FORM: WATERFALL BASIN
*BOOM*
The power accumulated in my legs erupted.
In an instant, a deafening boom split the air—the force of it tearing through the sound barrier itself. A shockwave blasted outward from the point of release, shaking the ground far below and shattering the silence of the sky.
The momentum of the blast was so great; it didn't just propel me—it slowed my fall, and the violent force counteracted gravity for a moment. My body, which had been plummeting helplessly seconds ago, now fought against the pull of the earth with raw, unleashed energy.
This was going to hurt.
Gritting my teeth, I stretched my body out mid-air, forcing my limbs into awkward, unnatural angles. Every muscle screamed in protest. I twisted, torqued, pushed my body into brutal contortions, desperately trying to redistribute the force of the fall, trying to bleed off velocity.
My muscles tensed beyond their limit—until one of them spasmed violently, a sharp stabbing pain exploding through my thigh.
Resulting in...
A cramp.
There was no foothold mid-air.No surface to plant my feet on.No solid ground to kick off from.
Which meant, realistically, there was no way in hell I could've recreated that move properly.
But—
Muscle cramps caused sudden, violent jerks in the body, uncontrolled spasms, and even mid-air, physics still cared about motion.
'I can use this.'
The sharp cramp that tore through my leg wasn't just pain—it was momentum.
Gritting my teeth so hard I thought they'd crack, I twisted my torso with the cramp's momentum, ripping my body into a wild spin. The spasm pulled my leg inward, which dragged the rest of my body along with it. It wasn't elegant. It wasn't clean. It looked and felt like complete chaos.
But—
It shifted my trajectory.
It wasn't much. A few crucial degrees.
But in a fall this fast, this high up—a few degrees could mean life or death.
I grunted, forcing another controlled spasm through my arm, bending my shoulder at a sharp, painful angle, jerking my path again. Bit by bit, like a broken marionette being yanked around by invisible strings, I started to manipulate my fall.
The word echoed in my mind like a war drum.
Every nerve in my body screamed in agony from the forced cramps—legs, arms, even muscles I didn't know I had—but I grinned like a lunatic as I saw the ground rushing up to meet me.
I could hear the whistling of the wind tearing past my ears. I could feel my bones rattling from the sheer velocity.
But none of that mattered.
I wasn't crashing anymore.
Focusing through the pain, I twisted my body one final time, aligning myself downward like a spear, hands together, muscles coiled tight.
"MARTIAL UNION WATER BREATHING EIGHTH FORM: WATERFALL BASIN"
I roared with every last ounce of breath in my lungs.
BOOM.
My body struck down like a meteor as my right leg struck the air just a second before I splattered to my death. The ground shattered beneath me, dust and debris erupting in every direction.
It wasn't nearly as strong or clean as my first attempt—the force was messy, uneven, almost desperate—but it was enough.
'I'm not dead'
I knelt in the shallow crater I had created, arms trembling violently, blood dripping from the corners of my mouth, every joint screaming in protest.
But I was breathing.
Alive.
Barely.
''Hah… Haah...''
I couldn't even breathe properly anymore-let alone move, but the grin never left my face.
Because against all odds, against every natural law that said I should have been a broken corpse—
I survived.
...
...
...
"FUCK, THAT WAS SO STUPID!"
I woke up with a gasp, the words ripping themselves from my throat before I could even think. Instantly, a white-hot wave of pain tore through my body, making me jerk and then freeze like a glitching puppet.
Especially my legs.
Oh, my fucking legs.
It felt like someone had taken a sledgehammer to my muscles and then wrung them out like wet towels for good measure.
"Ah—shit—!"
I hissed through my teeth, instinctively curling into myself, trying to massage the knots out of my thighs and calves.
Each movement was like trying to untangle barbed wire embedded under my skin.
"Stop moving."
Kenzo's voice cut through the haze of pain, sharp and steady.
I barely managed to lift my head before he appeared beside me in a blur, moving with a speed that made the world around him seem sluggish. In his hands, he carried a steaming tub of hot water and a bundle of cloth, the faint scent of herbs already wafting into the air.
Behind him, several Kakushi hurried forward, arms laden with rolls of bandages, jars of ointments, and strange-looking tools I didn't even want to guess the use of
"I thought this estate didn't have any Kakushi?" I muttered, flinching as one of them pressed a steaming cloth onto my leg.
"Yeah, we didn't," Kenzo growled from a few steps away, arms crossed tightly against his chest. He wasn't even trying to hide the way his jaw clenched with every word."The Stone Hashira never needed them. He never let himself need them."
Another Kakushi knelt beside me, working quickly and quietly, pretending not to hear the weight in Kenzo's voice.
"But now?" Kenzo laughed under his breath, a bitter, humorless sound. "Now we need an entire team... because some dumbass in this estate decided to throw himself off a cliff."
His words stung sharper than the hot cloth against my skin.
But when I risked a glance at him, I realized—his fists weren't clenched in anger. They were
trembling.
Just a little.
"I wasn't trying to kill myself..." I muttered, shame prickling the back of my neck.
Kenzo exhaled, low and rough. For a second, the fury slipped away, and all that was left was raw frustration—tinged with fear.
"Then what the hell do you call it, idiot?"
"That was..." I said, pausing for a bit "Re-assurance for myself?"
"What?"
"That move I did, means that I now know martial arts enough to use them in real combat" I continued, oblivious to his bewildered expression "This means, I can start pursuing other breathing styles now"
"Are you... serious?" he asked, his voice low, barely keeping it together. "You're telling me you jumped off a cliff—pushed your body to the brink—all for some fucking reassurance?"
I nodded slowly, still caught in my own head, the logic of it all somehow making perfect sense to me.
"Yeah," I continued, my tone growing firmer. "If I can handle that, I can handle anything—whether it's water, wind, or any other breathing style. It's about testing my limits, right?"
Kenzo exhaled again, sharper this time, and his gaze shot up to meet mine—furious and wide-eyed. His voice was a strange mix of disbelief and something else... maybe a bit of disbelief at the fact that he was seeing me like this, so lost in my own thoughts.
"You want to test your limits?" he repeated, his tone growing more strained, less controlled. "By nearly getting yourself killed?"
"Yes?"
"No. No," he snapped, his eyes blazing with a rare intensity I hadn't seen before. "You don't need to prove anything, you idiot. You think this is the way to grow stronger? By risking your life like a goddamn fool?!" His voice cracked, just barely. "You don't need to break yourself to get better."
"You think I don't care, don't you? You think this is just about me being mad at you for getting hurt. But it's more than that. It's more than just the fact that you're a pain in the ass to deal with..."
Kenzo didn't look at me as he said it. But I heard the weight in his voice—the burden of unspoken words.
"I'm just... so damn scared," he whispered, barely audible. "That you won't be here tomorrow. That I'll lose someone who... who means something to me."
'Mean something? We've only known each other for a week, haven't we? People don't get this attached this quickly'
'Just...' My eyes moved to Kenzo 'Just what kind of life has he lived...?'
It hit me like a punch to the gut. The tension in the room thickened, and for the first time, I realized that Kenzo wasn't angry just for the sake of it. He was terrified.
Tiredly, I sank back into the bed, the pain still throbbing in my leg, but now the emotional weight felt heavier than the physical. I let my eyes flicker up to Kenzo. There was so much unsaid between us—so much that we both had buried under layers of anger and pride.
"I'm sorry,"
...
For a moment, neither of us said anything; we just stood in silence as the Kakushi finally wrapped up my broken body and fled, likely from the tense atmosphere within the room.
"So," Kenzo muttered, looking at me, "Now what?"
"Now...I'm leaving."
"Leaving, huh? I figured"
No words needed to be said between either of us. I believe we both, no , maybe even Gyomei-Sensei, knew that I was going to leave one day to further my Martial Union. It wasn't simply because of the fact that I needed real battles to further my understanding, but rather-
"The breathing styles, huh?"
"That's right," I nodded, with a sharp gleam in my eye.s "It's time for me to learn other breathing styles."
Like how Water Breathing enhanced the mental and cognitive functions of the body, other breathing techniques enhanced other aspects of the body.
Just thinking about the other breathing techniques got me excited. Like, what would Thunder Breathing give me? Would I become fast as hell? Or what about Flame Breathing? Would all my attacks have a passive burn attribute?
What about Sun Breathing? What would th-
"Why are you training so much?' Kenzo broke my train of thought with a question "I understand your desire to grow strong, but where exactly does that desire stem from?"
"Where my desire stems from, huh?"
Truth be told, I had always wanted to become someone strong. To shatter the Earth and the Heavens and be free from all social and financial chains. To truly be the freest man in the world, with no one to challenge my authority.
No, that sounds a bit too cringe.
I guess it stemmed from my desire for happiness.
In my last-or even this world, no-one is truly completely happy. The poor struggle with survival, unable to provide themselves with food or shelter. The middle-class had food and shelter, but were unable to provide themselves the comforts and the luxuries of the house.
Even the upper class wasn't truly happy. While it may be true that Billionaires, with their insane amounts of money, could do practically whatever they wanted, they in exchange had to sell their souls and freedom, be bound by social constraints so they don't get cancelled, or spend entire months on some project that ultimately gets unnecessary hate simply because the middle class is envious of the upper class.
Make no mistake, the upper class was, is, and will always be happier than the middle class. Anyone who says money can't buy happiness is either an idiot or a rich person trying to stop others from reaching their status.
No, the point is, no one is truly happy. Sure, you may not have regrets at your deathbed, but is that because you're truly satisfied with how your life played out, or simply because you're now too powerless to actually do anything about it?
That's where my desire of power used to come from. If I were strong, I could lead a life without regrets, a life truly happy.
But now, my cause has changed.
It's no longer happiness that drives me.
"It's fear."
Because I have somehow found myself in TWO worlds that I, until a few months ago believed to be completely fictional. And if these fictional worlds are real, then that means the other fictional worlds are real too.
And that is terrifying.
Demon Kings are powerful enough to destroy worlds that are hellbent on destroying humanity, Apathetic higher-dimensional beings that could destroy all of reality by just showing their true form, terrifying ghosts and monsters unseen from the naked eye.
Even the very concept of Gods that humanity desperately clings onto may see humans as nothing more than playthings and pawns that they control to their amusement, uncaring of the impact on the human race.
Take Bleach, for example. Imagine you live a terrible life and when you die, you hope to go to Heaven because you lived a life free of sin, but instead you end up in Rukongai, A place where poverty and starvation are common, and you could die by Hollow Attacks.
The other alternative to Rukongai is becoming a mindless beast by the way.
Do you read those lines in novels that are meant to show the power a Protagonist possesses, and they hype it by saying they just destroyed a Universe? And how we completely overlook that line?
That Universe had people living in it, completely unaware that they were going to die because some edgy guy wanted to shoot a Ki-Blast or something. Just gone like that with no purpose.
What if that is MY WORLD?
FORGET all that god stuff, even in Demon Slayer Muzan Kibutsuji is an absolute force to be reckoned with. The only reason why Muzan lost in the manga was because of Plot Armor disguised as the drugs injected in Muzan.
Do you know the impact those drugs had?
The First stage was meant to convert Muzan to a Human, which obviously failed. The second stage was meant to age him by 50 years a minute. The third stage was supposed to stop him from splitting up, and the fourth stage was just complete cellular destruction.
And even after that, Muzan was able to keep up with multiple marked Hashira with the Red blade and would have won if Tanjiro didn't clutch up with the 13th Form .
What if something changes? What if the drug never gets completed, or what if Muzan simply decides to throw Tamayo away instead of absorbing her arm?
Absolute Annihilation.
The drug did 99% of the work against Muzan; without that, there was no winning.
And that was Muzan Kibutsuji. What about All For One? That guy was so strong he could survive nuclear bombs and change the weather on a global scale, and that was when he wasn't at full power either.
And I was AFRAID of that so much.
"Calm down."
Kenzo broke through my thoughts as I felt a warm hand on my shoulder. Immediately, I let out a large gasp, realizing that I wasn't breathing the entire time. I wiped my forehead, only for my hand to be completely covered in sweat.
"I--'m sorry, I got lost in thought."
"I understand," Kenzo said nodding "I too gained power because I was afraid of dying to demons."
'Oh? So he didn't join the Demon Slayer Corps to kill demons in the first place?'
"But..." he continued, locking eyes with me, searching. "Even I wasn't that afraid. No... I've never seen fear like yours."
He studied me, like he was trying to read a language written between the lines of my expression. "It's not just demons, is it? What are you really afraid of?"
'If only you knew'
I took in a sharp breath as I opened my mouth to speak, to tell him everything, to just desperately confide in someone.
And then, I closed it
"I'm sorry," I said quietly. "I can't tell you that. Not yet."
"...I see"
Kenzo muttered while looking at me. Slowly, he removed his hand from my shoulder as he got up, heading towards the door.
"If you need something, just call me."
I couldn't see his face, but I knew what expression he was wearing.
Disappointment.
Not at me, but at himself. And that made it worse.
*tuk*
The door was shut with a small thud, leaving me alone in the room with my thoughts.
No, not thoughts, there was only a single thought in my head.
"If I want to be free, if I want to be unafraid, if I want to boast my secrets, then there's only one thing I need to do."
My dull eyes brightened up with a newfound clarity as I looked at my room with a clear mind.
The world itself seemed to liven up as flowers bloomed and rivers flowed. The cry of newborn children could be heard, and the laughter of a family could be perceived.
Outside of this world, the mana in other worlds that were chaotic by nature calmed down, the Qi in the upper planes mellowed down, the chaos of the Outer gods seemed to dim, and the beings created from the negative concepts of life brightened up.
It was as if the infinite worlds that existed finally rejoiced at my newfound determination.
And above the mutants, heroes, mages, cultivators, Outer Gods, and concepts—beyond the infinite worlds, at the pinnacle of all that has existed, exists, and will ever exist...
Something smiled.
"I just need to become stronger."