After… I don't even know how many hours of honest, mutual violence, I realized something important.
Total Concentration Breathing on its own isn't enough.
While Total Concentration Breathing boosts your entire physical performance, basically making you capable of "fighting" an Oni... it's the Breathing Style that actually applies different forms of movement and action, using that strength efficiently.
In other words, it's the Breathing Style that turns raw power into technique.
Without a style, I was just a strong guy repeatedly punching an Oni, hoping something would eventually happen.
Does it work? Well… it worked this time, but it's not efficient at all.
My attempt to create a "rhythm" for Total Concentration Breathing was basically me fumbling around in the dark, trying to guess how a real style should flow.
Sure, it would be way easier to just learn a Breathing Style directly, but there was no one around to teach me!
I might've seen and heard the names of various forms from different Breathing Styles in the anime… but knowing the concept isn't the same as knowing the mechanics! That's the kind of thing that normally requires a master!
I know Water Breathing is about fluidity, Flame Breathing focuses on powerful, singular strikes, and Wind Breathing uses rotational movements… but what's the specific breathing pattern?
What's the exact timing between inhaling and moving? Which muscle tenses first?
The only thing I vaguely managed to reproduce was something similar to Thunder Breathing, because I remember the mechanics from when Tanjiro imitated it.
Basically, you concentrate all your strength into your legs and let it explode in a single breath to cut through the air in one burst.
I tried using it and I really did move way faster… but since Thunder Breathing didn't show up in my skill list, I'm guessing I just made some half-assed bootleg version.
I snapped out of my thoughts when I heard a short groan beside me.
He was finally showing real pain… but that was because the sun was finally rising.
That orange line on the horizon had started to stand out.
"Does that pain… make you happy?" I asked. I had the strange feeling I was witnessing something rare.
An Oni celebrating the arrival of the sun.
He was on his knees, head tilted toward the sun, even knowing what was about to happen.
Since I couldn't stick to my original plan of punching him nonstop until dawn, I had to cheat.
I grabbed some knives from the village stalls… but that doesn't count as stealing! I asked for permission, obviously!
A few villagers, after realizing I wasn't getting eaten, found the courage to come out.
It was an old man who handed me the knives with a trembling hand. "J-Just… just end this…"
Those knives were buried in the Oni's eyes now. I'd also cut off his hands and feet, which was pretty damn bloody, honestly. At some point, his regeneration just couldn't keep up anymore, so I dragged him out to an open area away from the village, and we waited there.
And with the sunrise, his skin began to sizzle, slowly crumbling into ash.
"Human… monster…" he muttered.
"Yeah," I replied calmly. "That's me."
Sunlight soon fully touched his body, and he began to fall apart. Like ash being carried away by the wind.
When he disappeared completely, I pulled the knives out and stood up, heading back to the village.
What? Was I supposed to feel moved by his death? Like that was ever going to happen!
Whether he regretted it at the end or not, whether he got his tragic flashback speech while dying or not, that was his problem! That doesn't erase the people he devoured!
We all carry "regrets". That doesn't mean our "sins" get forgiven.
You always have to deal with the consequences.
This time, I was the "consequence" for his sin.
But even if I had the moral high ground in this case, I still have to carry the "sin" of my own violence.
That's just how the world works.
…
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[Total Concentration Breathing <3/100>
Type: Technique
*Involves inhaling the maximum possible amount of oxygen through specific patterns to drastically increase blood flow and muscular strength.]
–––
"Three…"
After an entire night beating the shit out of an Oni and forcing my lungs like I was trying to blow up a damn balloon… that was the amount of "XP" I got.
It was less than I expected. I figured I'd get at least ten points, even if it was just symbolic.
"Alright. Total Concentration isn't something you master in one night of domestic violence…"
At this rate, following the anime's systematic training method would probably be more efficient. I at least needed to do the gourd training.
Training my lung capacity itself wasn't something I was worried about, since upgrading my Physical stat helped naturally.
But that's just raw capacity. Without technique, it's like having a massive sword but still swinging it around like a nervous peasant.
The gourd training is simple and straightforward, which means it's easy to practice. And with the Employee Profile, I can track my progress in real time.
'If I find some craftsman… can they make me a few sturdier gourds?'
The problem, of course, was still money.
I managed to get free food and new clothes, plus a day of rest in the village, but I didn't get any cash. Apparently, everyone needed it.
But at least I was recovered, full stomach and all, and I even got some spare onigiri, along with decent clothes, bottles of clean water, and some useful camping tools for staying in the forest, all packed into a backpack.
The fabric and stitching of the clothes still felt a little weird to me, coming from the modern world, but they fit this era just fine. Now I just need a haori!
After all, everyone knows the main characters among the Demon Slayers wear haori!
Of course… a sword would also be useful, even if it's not a Nichirin. Luckily, the old man told me that in a village toward Mount Akihara, he had an old friend who was a blacksmith.
For now, I'll have to make do with this pair of knives.
So when sunset came again, I continued my journey. The old man even gave me a general direction to follow.
"Head east until you reach the stream. Then go up the stone trail. If you get to a tree that's way too big… you've gone too far."
Flawless instructions.
'Seriously… I'd give up half my points for a GPS. God… I miss my phone…!'
Even so, I started walking. Yes, even with my long-standing record of being a sedentary bum.
And during the long walk, I took in the beauty of the night. Japan in this era is so… clean. Still mostly untouched by people and pollution, at least out in regions like this.
No power lines cutting across the sky. No constant engine noise. No industrial smoke in the air.
Just the breeze moving through the leaves, the distant sound of running water, birds calling out…
I stopped for a moment on a low hill and looked around. Endless vegetation, rolling hills in the distance…
The sky shifting between shades of orange and deep blue.
For a moment, I just closed my eyes and breathed.
It was peaceful enough to create this indescribable sense of fullness. Like, in that moment, I was wonderfully free.
You could almost forget there are man-eating Oni hiding out there somewhere!
Laughing at my own stupidity, I opened my eyes again and thought, 'My life really went off the rails…'
A few days ago, I was just a student with bad grades and tiny worries. Now I'm crossing Taishō-era Japan, looking for a blacksmith so I can officially start my career as a Demon Slayer.
But I'm not complaining. Even though some negative things happened —like dying— my life is in a moment of exponential growth, with a ton of possibilities ahead…!!!
Every step I take is my own choice! And it's that kind of freedom that fills you with anticipation!
…
The second night was quieter. I was already close to the stream the old man mentioned. At least the distant sound of running water suggested I wasn't completely lost.
The trail was uneven, with trees dense enough to hide anything bigger than a dog, but in that calm silence, the noise from the uninvited guest on my journey was irritatingly obvious.
"You guys seriously don't know how to take a day off, huh?"
He jumped out from behind a tree. His body was short, his eyes big, but he didn't have that irritating confidence the other one had.
This one looked more… hungry.
"Human…" he growled. His teeth were lightly chattering. "You're alone…"
I glanced around. "Looks like it."
He moved toward me, but compared to the previous Oni, it felt like he was running underwater.
I didn't even bother dodging. My fist hit his face before he finished his second step.
He spun on his own axis and fell sideways. When he tried to get back up, I was already beside him and kicked his knee.
The knee cracked and his leg bent the wrong way.
"… Ah," I tilted my head, "you're pretty weak."
He snarled and came at me hopping. I sidestepped, grabbed his arm, and pulled, using his own momentum against him. He slammed face-first into the ground.
I stepped on his back while he struggled, watching his knee regenerate.
'… regeneration really is the most impressive thing about them.'
I'd be lying if I said I wasn't a little jealous...
I yanked him up and smashed him against a tree trunk. His skull hit the wood and cracked.
"You…" he muttered. "You don't have a sword!!"
"You noticed?" I commented, seeing him glance toward my waist.
His eyes immediately started darting in every direction, calculating distance.
It wasn't hard to guess what he was thinking.
"Since you came all this way…" I stepped forward before he could twist his body away, "…help me run a few tests, yeah?"
He tried to jump back, but I lunged in.
My body shot forward and my shoulder slammed into his chest, knocking him back onto the ground.
"Test number one."
My extremely simplistic idea was to invent a Breathing Style, even if it was just something temporary that barely worked.
For that, the key points I considered important were cutting power, rapid forward movement, and continuous rhythm. In other words, a blade that was sharp, fast, and could keep cutting as long as needed.
I pulled out one of the kitchen knives I was carrying.
'If Breathing Styles turn strength into technique… then I need a rhythm that matches the concept.'
I exhaled and took a deep breath. "Total Concentration."
I came down with a horizontal slash straight at the Oni's neck. The knife sank in halfway… and got stuck in the bone.
His regeneration started instantly.
"Hmm… not powerful enough?"
He tried to grab me, but I rotated my body along with the next breath. This time I made the motion more rotational, using my hips.
The Oni's blood sprayed out, staining my clothes.
"Test two," I muttered, adjusting my breathing rhythm and beginning a sequence of continuous slashes.
He started screaming, his arms flailing without coordination. His regeneration tried to keep up, but the skin would rebuild… only to be torn open again immediately.
"Maybe…" I shifted the rhythm and focused everything into the next breath, compressing the force.
The knife drove into the side of his head, piercing just above the ear.
The sound was… unpleasant.
"Oh! Yes, that's the power!"
While mentally recording the sensation, the Oni suddenly turned and tried to run, the knife still embedded in his skull.
I found his attempt pathetic, but I mimicked the breathing rhythm and exploded forward in a burst, crossing the distance in the blink of an eye.
I caught up to him before he could take three steps, grabbed his hair, and yanked his head back.
"You were going to run? What about our collaboration?"
Without waiting for an answer, I ripped the knife out of his skull, spraying blood everywhere.
I adjusted my grip and tried to slice his neck this time, but I couldn't finish before the blade snapped.
I stared at the broken piece left in my hand. "… Seriously?"
Now I only had one knife left. 'The material isn't durable enough?'
The Oni tried to run again, completely abandoning any idea of counterattacking, but I knocked him down and planted my foot on his chest, keeping him pinned as he thrashed.
"Thanks for your contribution so far," I said politely, glancing at the horizon. There were still a few hours left until sunrise.
"How about we run a few more tests?" I asked kindly, but the look on his face gave me a very different feeling.
'… wait, why the hell does this look like I'm bullying an Oni?!!'