Faced with Shinji's "demands," Ubuyashiki naturally had no reason to refuse, nor would he have wanted to. The very purpose of the Demon Slayer Corps' existence was to slay demons.
Everything, whether people or blades, existed for that end. And now, a powerful yōkai had come bearing both the knowledge and the strength to kill Kibutsuji Muzan.
Even if Shinji had not asked for one himself, Ubuyashiki would have gifted him a Nichirin Blade regardless, to increase the odds of destroying the demons.
For a Demon Slayer Corps that, in this era, possessed no Breathing Techniques, the Nichirin Blades were of paramount importance. Yet what truly mattered was never the blades themselves, but the forging techniques and the raw materials.
However, the forging of Nichirin Blades was bound by a certain quota. The materials, though not extraordinarily scarce, were hardly abundant. Coupled with the immense difficulty of forging and high rates of attrition, each blade had to be custom-ordered in advance.
It required a wait of ten to twenty days. Shinji could not afford to wait that long. And so, he made his final decision: he would go himself, to the place where the Demon Slayer Corps forged their Nichirin Blades. He would forge the blade himself. One day would be enough.
To this as well, Ubuyashiki offered no refusal. Judging by his attitude… he even seemed to welcome it? That made sense. Though Shinji was a yōkai, he was a yōkai who had come bearing the personal letter of that great master smith.
And let it not be forgotten, the very origin of the Demon Slayer Corps' Nichirin Blades, that master smith Tōtōsai himself, was also a yōkai.
"Let the Kakushi guide you there, my lord," Ubuyashiki Rikiya had said at last. He left no room for the Seven Hashira present to object.
The so-called Kakushi were the logistical support unit of the Demon Slayer Corps. As a demon-slaying organization that had existed for centuries, the Corps' overall numbers were not large.
The swordsmen who actually hunted demons never exceeded three hundred in any given generation. The entire organization never surpassed a thousand members, scattered across the length and breadth of the land.
Lacking standardized equipment, wearing no armor, they could not compare to the top-tier daimyō of the realm. Yet they were, in their own way, fully functional. Within this structure, the front-line swordsmen suffered an appallingly high casualty rate.
The demands on them were, naturally, correspondingly extreme. To qualify, one had to survive the ordeal deep within the wisteria-surrounded "Mount Fujikasane," where a small number of demons were held captive.
To survive there for seven days and seven nights and prove one's ability, only then could one serve. It was a trial of staggering mortality, offering no guarantees. Pass and live. Fail and die.
But not every member of the Demon Slayer Corps was required to stand on the front lines. The senior swordsmen responsible for training and evaluating new recruits assessed their abilities, and, more importantly, their own willingness. Those who could not, or did not wish to, participate in the Final Selection and become front-line swordsmen were assigned to intelligence relay, medical support, corpse disposal, and every form of covert, behind-the-scenes work.
They wore masks. They never revealed their true names. They operated under aliases. These were the Kakushi, the hidden members of the Demon Slayer Corps. The one guiding Shinji to the Swordsmith Village was code-named Chō, Butterfly. A single character.
Before setting out, Shinji swept a glance over Chō. With Yoriichi's wife nearing her due date, expected within the next few days, Yoriichi had not accompanied them this time.
It was just him and this clearly female operative. The Chō he saw before him was not tall, a full head shorter than Kikyō. But her walking pace was extremely swift. Her rapid little steps pattered as she chased after Shinji, her slender legs pumping as though wound tight as clockwork.
The hem of her white robe, patterned with violet, fluttered at the edges. She wore a butterfly-patterned mask. Everything below the bridge of her nose was exposed. Her lips were pressed tightly together, bearing the expression common to young people in the presence of something far stronger than themselves, a mixture of pride and envy.
"Pardon me, Sir Shinji," she began. Her voice was clear and crisp, each syllable enunciated with deliberate precision, clearly the result of rigorous training. "You said you would only need a single day to forge a Nichirin Blade…"
"Mn." This was indeed what Shinji had told Ubuyashiki.
"Is that… truly possible?"
"Mn."
She paused. "That 'Mn' means…"
Shinji glanced at this girl again. She talks quite a bit, doesn't she? But it didn't matter. It passed the time.
"It means yes," he said. He walked on. His white, flowing hair drifted in the mountain's morning breeze. His bamboo hat hung against his back, his straw rain cape wrapped over his gray robes.
Chō chased after him a few more steps. When she spoke again, her voice was laced with even more careful caution than before.
"The smiths of the Swordsmith Village… they can be somewhat difficult. They are extremely stubborn about matters of the blade. They don't take kindly to outsiders claiming things like 'one day is enough.' Not long ago, the Master invited a very powerful onmyōji, saying he could help accelerate the forging process. And then—"
"What happened?"
"He was chased out. They said he 'ruined the iron's temperament.'"
Shinji turned his head and looked at her. "The iron's temperament." He rolled the phrase over in his mind and nodded.
"That's a discerning view."
All things possess spirit. Anyone could say those words. But very few could truly practice them. Shinji, who possessed the System, understood this more deeply than most. He'd heard no shortage of complaints from various objects.
Chō blinked, clearly not expecting such a response. It took her a moment to continue. "So you mean… you truly can finish it in one day, but without destroying the iron's 'temperament'?"
"Mn."
"Then… how will you do it?"
Shinji didn't answer right away. He stopped beside an old pine leaning crookedly by the roadside. He reached out his right hand and pressed his palm against the tree's bark.
Chō stopped as well and watched him, her face a mask of pure confusion. After a long moment of silence, Shinji removed his hand and continued walking. "Even if I told you, you probably wouldn't understand."
Chō stood frozen for two seconds before scrambling after him. She didn't press further. She simply walked half a step behind, occasionally stealing rapid glances at him, as though pondering something, or perhaps mulling over words she hadn't yet spoken.
They were likely the reminders Ubuyashiki had instructed her to convey to Shinji. But Shinji paid it no mind at all. Throughout the journey, the girl code-named Chō seemed to waver on the verge of speaking multiple times, only to swallow her words again.
She wrestled with herself, unable to find the right moment, yet too afraid to force it. The Master had given his orders: though this one was a yōkai, he was the most honored of honored guests. To be discourteous was absolutely forbidden.
But in truth, Shinji recognized this girl. Even though only half her face was visible, he still knew her. Not this era's version of her, though. He knew another version. Or, to use this world's terms, it must be her future life. Kochō Shinobu.
The Butterfly Hashira from the main storyline of Demon Slayer, the girl who always wore that dangerous smile, the swordsman who substituted poison for a blade, using medicine to gouge holes through the undying bodies of demons.
He had already confirmed it: reincarnation was real in this world. Setting Kikyō aside for the moment, there were incarnations of Bishamonten here. Vestiges of gods and buddhas.
Existences like Tsugikuni Yoriichi, who came from some distant shore and went toward some far destination. Reincarnation was not strange. What was strange was that he was meeting, here and now, the one who would one day become the Butterfly Hashira.
He studied her for a moment. He didn't reveal it. There was nothing to say. She was who she was now. The future life was the future life. Her path, she would walk it herself.
The Swordsmith Village was on no map. The road was something you walked into existence. A stretch of dirt path. A stretch of mountain trail. Through two groves of bamboo.
Finally, they turned onto an old flagstone road nearly swallowed by weeds. Without a guide, this place would indeed be difficult to find, even for Shinji, even through "asking the stones."
The moment he saw the cooking smoke, he smelled it first. Iron. That scent of molten iron and stone, just drawn from the furnace, thick with heat. Not dense, but continuous. As though it had drifted out on the wind from the deepest heart of the valley.
Chō walked a few steps ahead, then looked back. "We're almost there. Someone will meet us at the village entrance." She paused. "Sir Shinji, with the smiths… if it's at all possible, could you try to be a little… polite?"
"I'm always polite."
Chō glanced at him. Something unspoken lingered in her eyes. Shinji paid her no mind and kept walking.
The people of the Swordsmith Village received Shinji with proper formality, respectful, courteous, full of decorum.
The village headman was named Ishida. Past fifty, his hair already graying. His hands, deformed by years of forging, were yet still nimble. Those hands rested on the teacup, so steady that not a single ripple disturbed the surface of the tea.
He had already read and confirmed Ubuyashiki's letter. His expression was one of deference.
"Lord Shinji's request, we have already been informed by the Master ahead of time," he said, his voice deep and low. "We have heard that you are acquainted with Master Tōtōsai. It is only a pity that our own master smith has already passed. He could not meet you."
That man had been human, after all. Both Shinji and Tōtōsai had guessed as much. After a pause, Village Head Ishida continued. "But you must also understand, a single Nichirin Blade, from ore selection to forging, to quenching, to polishing, to complete the entire process, ten days is the absolute minimum. Sometimes, when the iron is uncooperative, it drags on to half a month. Even a full month."
"I know," Shinji said, seated across from him. His crimson demon eyes were calm. His tone was even calmer. "That's why I don't intend to use your methods."
The smith's fingers curled inward slightly. "Then… what method does the gentleman intend to use?"
"I know the Nichirin ore is in the mountain behind the village. I will go up myself and select the iron ore. Then, in a single day, I will finish it on my own."
The silence that passed through the Swordsmith Village lasted at least half a quarter of an hour. In the end, it was Chō who let out a very small sigh.
She had known it would be like this. People with ability were always a little eccentric. How much more so a yōkai?
But still, out of regard for Ubuyashiki, or rather, out of regard for the Tōtōsai who stood behind Shinji, the smiths ultimately held their tongues. They wanted to see what this outsider, this young man, truly intended to do.
The mountain rose behind the village. Not particularly tall, but dense. The veins of scarlet ore were exactly where Shinji knew they would be, hidden at the mountain's highest point, closest to the sun.
Under the blazing sun's relentless baking, the color of the stone was deeper than that found outside. In the early morning light, it gleamed with an exceedingly faint orange-red.
Because it had been seared by the blazing sun for so long, only thus could it carry the sun's energy within it.
Shinji went up alone. The people of the Swordsmith Village did not follow. They only stood at the foot of the mountain, watching from a distance as that gray-robed figure ascended the slope. Chō accompanied him to the edge. "Do you need me to accompany you inside?"
"No."
"Very well. Though there is no danger within, please still take care. I will wait for you out here." She did not press further. She retreated to the base of the mountain and stood there, waiting. Her eyes, behind the mask, watched him disappear among the shadows of the trees.
Shinji spent an entire day on that mountain. But he did nothing. No forging. No hauling ore. He didn't even draw his blade. He simply walked. From this stone to that stone. From this ore vein to that rock face.
Wherever he walked, he stopped. Crouched down. Pressed his palm against the surface. Sometimes he stayed a very long time.
Sometimes he only patted it lightly twice before rising and moving on. Occasionally, he spoke. His voice was so low that even the forest breeze swallowed it.
Only he knew what was said. And the stones, they, too, stirred with the faintest of movements. A piece of gravel rolled two turns. A bubble rose from a crevice in the rock.
A patch of the ore face deepened just slightly in color. All of it was so subtle. Without paying close attention, one would see nothing at all.
The smiths waiting at the foot of the mountain, however, could notice. They took turns keeping watch beyond the tree line. Every so often, they would glance into the depths of those tree shadows.
They still couldn't discern anything meaningful. All they could do was exchange glances, furrow their brows, and swallow their confusion. Village Head Ishida crouched on a stone beyond the tree line and watched in silence for the greater part of the day.
In the end, he simply drew on his pipe and exhaled two words into the evening mountain wind. "A peculiar man."
Chō heard him. She didn't respond. She stood at the mountain's base for the entire day, even eating her lunch there, never once leaving. She couldn't quite say what she was waiting for. She only felt that something was about to happen. And she didn't want to miss it.
Noon of the second day. The sun had climbed to its highest point. A lazy warmth baked into the mountain air, and even the atmosphere itself seemed to grow sluggish.
The smiths ate when it was time to eat, rested when it was time to rest. There were still those keeping watch at the mountain's base, but their alertness had dulled since yesterday.
They'd waited an entire day yesterday. Surely they wouldn't have to wait again today?
"He's moving," a young smith keeping watch by a tree suddenly spoke.
Every head lifted at once. From among the tree shadows, Shinji emerged. White, flowing hair. Gray robes. His crimson demon eyes glowed faintly beneath the midday sun.
The moment he stepped past the tree line, he stopped. He turned, facing the direction of the mountain's heart. He bowed his head slightly and spoke a single, very soft sentence.
The voice was so small that only Chō, standing closest, faintly caught three words. "I'll trouble you."
Then he lifted his head and walked toward the smiths. They looked at one another, utterly bewildered. No one knew to whom those words had been spoken.
"Sir, you've…" Village Head Ishida stood up, having even forgotten to hold his pipe. "Have you finished selecting? Where's the ore…?" He couldn't finish the sentence. Because the sound from the mountain had arrived.
It wasn't the common rumble of a landslide. Nor was it falling rock. It was something smaller, finer, yet in the silence of this mountain valley, it was so sharp and clear it made one's spine prickle.
The iron ore was moving. Not dug out. Not hauled. Moving, on its own. The scattered scarlet iron sand within the veins. The ore embedded deep within the rock faces. Piece by piece, they dislodged themselves from their places.
They gathered. Flowed slowly down along the dirt channels and crevices within the mountain's heart. Like a thin stream of scarlet, flowing out from the mountain's belly. Flowing into the old workshops the smiths had long left upon the slopes.
No one lit the forge. The flames in the furnace kindled themselves. Their color was purer than usual, carrying a red almost entirely free of impurities. Steady to the point of absolute stillness, not a single flicker. The leather bellows inflated on their own.
The anvil beside the forge shifted slightly, as though adjusting its own position. Within the entire workshop, everything that should have been operated by human hands began to move. The iron ore melted in the furnace, becoming liquid scarlet iron.
Then, guided by an invisible force, it flowed into the mold. Cooled. Took form. Then, of its own accord, it was repeatedly folded and hammered. The sound of the hammering was even and rhythmic.
Every blow landed with perfect force, at the perfect angle. Not a single deviation. Throughout the entire process, not a single human hand intervened.
The smiths stood outside the workshop. On the threshold. In the courtyard. Watching all of this. In utter, breathless silence.
The old smith's pipe dropped to the ground. He didn't pick it up. His clouded eyes remained fixed on the forge that was hammering away entirely on its own. He did not blink for a very long time.
Chō stood three paces away from Shinji, also watching. As a Kakushi of the Demon Slayer Corps, though she was not required to fight on the front lines, she had seen her share of things ordinary people would never have the chance to witness. Blood. Death. The supernatural power of demons.
But this scene still shook her. Iron, was forging itself. Fire, was burning according to its own will. A Nichirin Blade, with no human smith lifting a single finger, was progressing from raw ore to finished form step by step, at an efficiency that did not belong to this world.
"This is…" She swallowed softly, suppressing the shock in her heart. "How did you… how did you do this?"
Shinji didn't answer right away. He simply placed his hand on a pillar beside the workshop, his palm pressed against the wood, his tone utterly casual. "Artifacts have spirit. Speak with them. Tell them what you want to do. Tell them you need them. Tell them you know they can do it. And then—wait."
"Wait for what?"
"Wait for them to decide to help you."
This was what Shinji had been doing the entire day. He had learned the craft of smithing from Tōtōsai, but the true essence had never lain on the surface. It was this: the exquisite fusion of cultivation and forging. That was why he had come.
He would not break the "temperament" of artifacts, or rather, their spirit. He would simply let them help him complete this step on their own. All things possess spirit. And those who walk the Way, find aid in abundance. This was Shinji's Dao.
Chō stared, momentarily stunned. She looked at the pillar beneath Shinji's hand, she could have sworn the grain of that wood had grown just a shade brighter, gleaming with a luster no timber should possess, something almost joyful.
Then she looked back at the heat-hazed furnace and the self-operating forge within the workshop. Inside, the scarlet iron ore let out a crisp, resonant ring at that very moment, as though in answer.
Shinji tilted his head slightly and glanced in that direction. The corner of his mouth tugged faintly. "The rest," he said, "is their own affair." He withdrew his hand from the pillar, turned, and walked beneath the covered walkway, settling himself down.
Casual. At ease. As though everything was within expectation. As though there was nothing remarkable about any of it.
The old smith stood at the entrance of the workshop. No one knew how long he had stood there. At last, he slowly bent down and picked up his fallen pipe from the ground.
He didn't speak. He only held the pipe in his hand and exhaled, very softly. That breath was mingled with thirty years of a smithing life, and the heavy, trembling sigh of seeing, for the first time, something he had once believed to be mere legend proven true with such effortless ease.
He had heard such rumors before. He had heard that the greatest master smiths could create objects that seemed to be works of nature itself, as though they had grown into their form on their own.
Objects that truly captured the divine in craftsmanship. And now, he had seen it. Though it was not quite the same, it returned by a different road to the same destination.
The finest art of smithing had never been about forcing iron to take shape according to human will. It was about letting iron, following its own will, take shape on its own. He knew this truth. Every smith knew it. They had spent their entire lives chasing it.
When they couldn't reach it, they passed the words down to the next generation, for the next to continue the pursuit. But the one before him had, in a single day, with a few words spoken to stones, effortlessly accomplished it.
"Remarkable," he said at last. Just that one word. No flattery. Only a gravity that rose from the marrow of his bones.
Chō heard him. She didn't speak either. Her gaze shifted from the Nichirin Blade taking form inch by inch within the workshop to the gray-robed figure seated beneath the covered walkway, eyes closed in rest.
It rested at last on that cold, severe face, devoid of all expression. But her own eyes, were alight. As a Kakushi of the Demon Slayer Corps, supporting and aiding the swordsmen who fought on the front lines, she had studied medicine. She knew a little about identifying minerals. She even understood the basics of smithing.
And she knew what those iron ores had stored within them. Centuries, millennia, of unbroken, day-after-day sunlight. What they had accumulated, perhaps, was patience. And what that yōkai before her had taught those ores… was precisely the same thing. Only, his patience was pointed in a different direction.
One day. One instant. Nichirin Blades that should have taken at least ten days, even a full month, to forge were completed in less than a quarter of an hour. Yes. Not just one blade. But a full armory's worth. Nichirin Blades.