Chapter 6: Arasaki Tetsushin
The unease in Asuka's chest deepened. For a moment, he didn't want to speak.
But he knew better than anyone that the danger radiating from the old man before him was not something he could resist.
Rukongai had taught him its second most important lesson:
Before you have strength, don't bark at big dogs.
He stayed silent for a few seconds before finally speaking.
"…Asuka."
"Do you have a family name?"
"…Seventy-Eight."
"Mm…"
The old man didn't pursue the matter.
In times like these, nameless street children were everywhere—wandering the alleys until they were either eaten by demons or sold off by people whose hearts were blackened beyond redemption. Whether one had a surname or not meant little.
"Asuka," the old man continued, "the wounds on your body were caused by a demon. Three of them should have been fatal—and yet you survived. Your vitality is remarkable. Don't waste it."
As he spoke, he passed the bowl of medicine to Asuka again.
Seeing the lingering distrust in the boy's eyes, he said in a low voice,
"I can tell that your presence is different from theirs. I understand the difference between a street orphan and an ordinary civilian. But here, everyone is the same."
"If I wanted to kill you, I wouldn't need to go to such lengths."
Asuka twitched the corner of his mouth.
Annoying as it was, the logic made sense.
He stopped resisting, lifted the bowl, and drank the bitter medicine in small, steady sips—finishing every last drop without spilling any.
The old man nodded, then pointed to himself with his remaining right hand.
"My name is Arasaki Tetsushin. This is my training hall—Hayama. A place dedicated to cultivating swordsmen for the Demon Slayer Corps."
"You've already seen what demons are. That much is my failure—I didn't expect one to be lurking so close to Hayama without my noticing."
"Ordinarily, those who wish to become disciples here must pass a number of basic trials…"
"But for an ordinary human capable of killing a demon, I believe such tests are unnecessary."
Arasaki Tetsushin then pointed at Asuka and asked the question he cared about most.
"The Demon Slayer Corps reported extensive torn blade marks at the scene. Boy—how did you do it?"
Asuka's pupils contracted sharply.
Arasaki caught the reaction at once, his expression turning grave.
What do I do? Should I tell him?
Asuka's thoughts raced, already trying to construct a story.
He remembered fragments now—the battered blade in his hands was a special weapon called an Asauchi, capable of resonating with its wielder's inner world and releasing unusual power.
But he didn't understand whether he had truly mastered it. And more importantly—this power clearly didn't belong to this world.
If he told the truth… would it bring him trouble?
Before Asuka could answer, Arasaki Tetsushin spoke again, as if offering him a way out.
"I've lived for decades," the old man said calmly, "and I've heard of rare individuals—those born with an instinctive grasp of Breathing and sword intent."
"…Could you be one of them?"
"Breathing…"
Asuka opened his mouth. Caution and cunning quickly stitched together an answer.
"I… don't really know. I only remember wanting to avenge the old man. I was angry, swinging wildly…"
"Sometimes the blade would carry a… wind, like dogs howling—completely out of control. Other times, it just felt like my strength suddenly increased…"
Arasaki listened in silence as Asuka's explanation wandered, fragmented and confused.
"An uncontrolled wind…"
He could sense the flow of energy within people.
The boy was lying—but not entirely fabricating things. It sounded more like exaggerated metaphor than pure invention.
Is he overstating his strength to intimidate me?
Or is this simple distrust—trying to protect himself by appearing dangerous?
Arasaki studied Asuka for a long while, observing the flow of his aura—a faint reddish current. Hostile, yes, but not malicious or calculating.
Self-preservation…
That was his conclusion.
"…Very well," Arasaki said at last, his voice steady and resolved.
Perhaps this was simply a rare, unrefined combat instinct—untutored, unshaped. That explanation fit best.
"Whatever it is, the fact remains—you killed a demon. Use that power well. It will become one of the pillars that allows you to survive."
"One of them?"
Asuka echoed the phrase, puzzled.
By then, Arasaki Tetsushin had already risen.
He walked to the door of the room and slid it open. Without turning back, he left Asuka with a final sentence:
"Hayama is not a lawless street. No one here will steal your food or harm you without cause."
"When you can stand on your own feet…"
"I'll show you what real wind looks like."
The door slid shut, cutting Asuka off from the outside world.
He sat there in silence, staring at the unreal warmth of the room before him.
After a moment's thought, he crawled back to the Asauchi, pulled it into his arms, and burrowed into the still-warm bedding, wrapping himself up carefully and tightly.
Maybe it was something Arasaki's words had stirred in him.
Or maybe he just wanted to cling to a few more days of safety.
Either way, he soon slipped once again into a heavy, drifting sleep.
---
Several days later—outside the training grounds.
Only when Asuka finally stepped out of the tatami room did he realize that Hayama wasn't just a single building, but a connected complex of structures spread across nearly half the mountaintop.
The training grounds themselves were divided into indoor and outdoor areas. What Rika was leading him toward now was an open, windswept clearing carved into the western slope near the summit.
The wind up here was sharper, colder—carrying fine snow and dry leaves that quickly reddened exposed skin.
Asuka stood at the edge of the outdoor training field. Over his clothes, he wore a light-green kendo uniform Rika had brought him—clearly not his size. Beneath it, he still had on the old cotton coat left by the bald old man, now washed and carefully mended.
The temperature was low enough that, under normal circumstances, no one would let a recovering patient out into the wind.
But Asuka's vitality really was as Arasaki had said—abnormally tough.
In just a few days, with the help of medicinal herbs, his wounds had scabbed over and begun to heal. Even Rika had been surprised.
Large movements still brought dull aches—but he could move freely, and that alone satisfied him.
The battered Asauchi was still tied at his waist.
His eyes never left the tall, one-armed figure standing in the center of the field.
Arasaki Tetsushin.
The old man wore the same plain clothes as always, but today, a heavy, weathered wooden sword rested in his hand.
He stood quietly, facing the layered mountain peaks in the distance—so still that he seemed to merge with the howling mountain wind itself.
"Watch closely, boy."
Arasaki didn't turn around, yet he had already sensed their arrival.
"This is—the Breath of Wind."
The instant those words fell, Arasaki Tetsushin's presence changed.
Moments ago, he had been like part of the world itself—formless, fused with sky and mountain air.
Now—
He was like a blade drawn from its sheath, cleaving the atmosphere in an instant.
Like a sudden tornado erupting from flat ground, crashing violently into Asuka's perception!
Arasaki tightened his grip on the wooden sword and raised his single remaining arm.
A vast, razor-sharp killing intent surged from his body—violent enough to tear everything apart!
Whooo—!
The wind trembled with his breathing.
The air hummed with his movement.
Threads of pale blue-white vapor hissed as they poured into his lungs, transformed into raw, explosive power that surged through every limb!
Around the wooden sword, chaotic currents coiled—condensing into something almost tangible, glowing with a vivid emerald light!
"Breath of Wind—Fourth Form:
Rising Dust Storm!"
Arasaki lowered his stance and barked the words.
The wooden blade carved a wide arc before him, rising from low to high in a ferocious upward sweep—
SHRRRRAAA—!!!
A piercing explosion of torn air detonated across the field. Asuka's ears rang violently, his vision blurring in an instant.
And in the next heartbeat—
He witnessed a sight he would never forget.