The mountains of Kōzuke Province were not particularly steep, yet they stretched endlessly deep. Dawn had just barely broken, the morning mist still clinging damply to the earth.
Along the gravel path at the mountain's foot, a young man approached. Very young, barely past twenty. He wore a patched, faded red outer robe. A nondescript hatchet hung at his waist. On his back was an empty bamboo basket. His hair was a deep crimson, bound high, the ends curling slightly.
What drew the eye most was his forehead. At his left temple was a deep red mark, like a blazing flame. From his earlobes hung a pair of ornaments, hanafuda earrings, painted with the pattern of the sun, swaying gently with each step.
He walked with remarkable steadiness. But it was not the steadiness of a samurai deliberately lowering his center of gravity, nor the light, silent steadiness of a shinobi.
It was a naturalness, as though he had merged completely into his surroundings. His feet tread upon dead branches, but the branches gave no brittle snap. The hem of his robe brushed dew-laden blades of grass, yet the dew did not fall. His breathing was long and deep, his heartbeat slow.
He moved like a wisp of wind wandering through the mountains, or a beam of light filtering through the treetops, utterly devoid of the jarring presence of the living.
But in this very instant, this very second, the young man suddenly stopped walking. He lifted his head. His deep crimson eyes gazed ahead. There lay a nameless hill. Not particularly tall, but its view was superb, overlooking the castle town below that had yet to stir awake.
"…Strange," the young man murmured. He said it was strange, yet his voice was flat, without much inflection. No surprise could be heard. It was only that, in his field of vision, the hill ahead was indeed deeply wrong.
Not wrong in the way of yōki bristling with menace. Not wrong in the way of reiryoku surging and clashing. It was a strange, inexplicable change.
The wind was blowing from the southeast. By all logic, the grasses and trees of the mountain should have been bending northwest with the wind. The leaves should have been swaying to one side. Even the morning mist should have been flowing along the veins of the breeze. The surroundings the young man observed were indeed like that.
But that hill was different. The blades of grass did not follow the wind. They all stood perfectly erect, and even bent slightly inward, pointing toward the summit.
The branches of the trees stood utterly motionless, as though frozen in place. Every limb strained, reaching as far as it could toward that highest point. The scattered stones on the ground, which should have lain in haphazard disarray, now seemed as though they had been meticulously arranged by someone's hand.
Even the mist had stagnated there, forming an immense ring, not dispersing, not disturbing. All things held silent. But it was not fear. It was… clustering. Like subjects clustering around their sovereign. Like worshippers paying homage to a deity. It defied all reason.
Grass, trees, and stones of the natural world had no consciousness. They followed only the laws of wind and gravity. And yet, they also possessed spirit. It was simply that this spirit was exceedingly difficult to awaken.
And now, they had unquestionably awakened. Such a scene unquestionably meant one thing: atop that hill, something existed that they found more worthy of "closeness" than wind or gravity.
The young man did not retreat. Within those eyes that could see through to the essence of all things, he saw no malice. Only a pure, vast, coalescing Will.
He began to ascend the hill. His steps remained steady. Each footfall landed in the gaps the grass and trees made way for. The higher he climbed, the stronger the sensation grew. The wildflowers along the path strained desperately to unfurl their petals, even though it was nowhere near their season.
The soil beneath his feet was even firmer, more level than elsewhere, as though it had actively compacted itself to bear the figure upon the summit. And so, after a few more steps, the young man stopped walking. Because he realized: this mountain was rejecting him.
Or rather, it was rejecting the presence of anything that was not among those who clustered around that figure. And that naturally included him.
But the young man no longer needed to walk further. Standing at the foot of the hill, lifting his gaze, he could see the summit. He could see the being who was clustered around.
The figure who was "close" to all things. It was a figure seated upon the grass at the top of the hill. Seated beneath a tree, as though seated upon carpets beneath a canopy.
A being who was not human. A demon. Clad in gray robes. Pale skin. White hair tied loosely behind his head. He sat cross-legged, his spine straight as a spear.
Across his knees lay a blade still sheathed. His eyes were closed the entire time. He did not move. Seemingly unremarkable. No breath. Not the slightest motion. A demon, yet more akin to a plain, featureless statue.
But in the young man's eyes, it was anything but unremarkable. It was a vast, churning vortex. All the wind, the light, the air currents, even the vitality of the grasses and trees, was being drawn into that body.
It was an existence like a black hole. Yet even as it devoured, it radiated outward a piercing, incomparably sharp Will. Full to the brim, and overflowing. That was a sword. Within that person's body, a sword was taking shape. Not a blade of iron held in the hand, but the Will of the heart.
The young man simply stood there, watching. He made no attempt to draw closer. Because he felt that if he took even one more step forward, he would disturb that delicate balance. Time itself seemed to lose all meaning of flow in this place.
Until the first true ray of sunlight pierced through the clouds and fell upon that person's face. That person opened his eyes. Black sclera. Crimson pupils. Deep within those pupils, violet veins and orange luminescence intertwined, finally converging into a single point of ultimate sharpness.
Hum—
The katana across his knees emitted a crisp, resonant ring. All around, the inwardly bending blades of grass, the frozen tree branches, the solidified mist, in that single instant, as though granted absolution, abruptly relaxed.
The wind began to flow again. The grass began to sway once more. The world restored its original order.
Shinji exhaled a breath of impure energy, yōki.
He then lowered his gaze, looking downward, toward the foot of the hill, 30 metres away in a straight line, where a young man with crimson hair stood.
Their eyes met. Crimson demon pupils locked onto deep crimson irises.
Shinji's fingers rested on the hilt of his blade. He did not move. He hadn't yet had the chance to carefully savor the effects of the Sword Will that had just taken its final form, or what it would become once poured into the demon blade Onikiri at his waist.
He hadn't yet had the time to reflect with satisfaction that the casual Affection he had spread along his journey, scattered among all things, had not been in vain. Though only a few points, a dozen or so here and there, the myriad things of heaven and earth truly came to his aid when he needed them.
The grass, the trees, the stones, the soil, this very mountain, had all been standing guard for Shinji moments before. Not enough to repel a true foe, but more than capable of serving as a warning.
Looking at the young man before him, Shinji's mind went briefly still. He recognized him. To be precise, he recognized that attire. He recognized the unmistakable crimson mark upon his forehead. And those earrings. That patterned scar.
This was… Tsugikuni Yoriichi. The man known as the pinnacle of combat power in the world of Demon Slayer. In the worldview of Demon Slayer, aside from the Nichirin Blades, the other great pillar upon which the Demon Slayer Corps relied in their battle against demons, the Breathing Techniques that granted their users superhuman physiques and combat prowess, originated from him.
He was the so-called Sun Breathing swordsman. He had never expected to meet him here. Like this.
Shinji rose from the summit. Onikiri at his waist hummed one final note before falling silent. The blade-soul had taken form. Complete. No longer a half-finished product, but a soul approaching perfection.
He could feel it. Within that blade now lay an entirely different weight. Not the weight of accumulated yōki, but the weight of condensed Will. Blood-Fire had cut down demons. Sword Will had returned to one.
The soul of that blade had, at last, in this very moment, caught up to his stride. Though it could not yet assume a "human form", even an illusory, phantom shape rather than a true body, it could now move of its own accord, if it so willed. It could be called a tsukumogami. And in time, through further transformations, it would learn to conjure a form.
But throughout all this, Shinji's gaze never left the foot of the hill. The young man with crimson hair was still there. He had neither left nor drawn closer. He simply stood, watching Shinji with those deep crimson eyes. No alarm. No retreat. Even the position of his hand on his blade hadn't changed.
That hand rested on the hilt of the hatchet at his waist, light and casual, merely hanging there, propped, not gripping. But Shinji knew: if he truly made a move, that hand could complete its draw in a single instant. The reason was simple. The name Tsugikuni Yoriichi alone was proof enough of such ability.
And so, calm of expression, his cold features perfectly still, Shinji descended the hillside. Not fast. Drawing near, he stopped three paces away. Up close, the young man's contours were sharper than they had seemed from the summit.
Barely past twenty. Slightly lean of build. His red outer robe bore several patches. The deep crimson mark at his left temple was oddly shaped, like a flame frozen upon his skin. His features could not be called strikingly handsome. They were merely well-proportioned.
\What was most peculiar was his presence. He breathed, but that breathing melded so seamlessly with the mountain wind that it scarcely seemed the respiration of a living being.
He seemed more like something that had always belonged to this mountain. A tree that had grown here. A stone embedded in the earth.
Shinji focused his senses. A term surfaced in his mind. Or rather, the Breathing Techniques. Those arts cultivated by the swordsmen of the Demon Slayer Corps within the world of Demon Slayer.
The lungs made a forge. The breath made a blade. Muscles, bones, and blood were pushed to their absolute operational limits, compensating for humanity's inherent physical disadvantages.
But in truth, this ability to focus on the breath to enhance one's own physique was never exclusive to the swordsmen of the Demon Slayer Corps.
In fact, it was a practice long utilized by the vast majority of samurai, swordsmen, and warriors. Whether it was the Jigen-ryū, which adjusted large gulps of inhalation and exhalation to inflate fighting spirit, or the Tenshin-ryū, which used breath exchange to rapidly shift between high, middle, and low stances, all incorporated the function of breath.
Yet Shinji had never, in any dojo of any school, in any human swordsman he had encountered thus far, felt a presence like this. A presence so perfectly attuned to the natural world. This was the true effect of taking the characteristic of "breath", something all living creatures shared, and refining it to its utmost extreme.
Only breathing refined to this degree could truly be called a Breathing Method. As expected of the progenitor of all Breathing Techniques, the Sun Breathing swordsman.
Amidst this, the young man had not spoken either. He merely studied Shinji. His gaze paused for an instant on the pale face where the demon mask had vanished, then fell to the Onikiri at his waist, and finally returned to his eyes. Black sclera. Crimson pupils. Human-like, yet not human.
"…Sir. Forgive the intrusion." He spoke first. His voice was not loud. His tone was flat. Shinji understood. Those words were both greeting and confirmation. He hadn't drawn his blade simply because he saw a yōkai. He just greeted him, normally.
"No intrusion at all," Shinji replied, neither warm nor cold. Yet there was no trace of the anger of one who had been disturbed, nor any intent to drive the other away.
The young man's expression remained calm, as though his heart had settled. "It seems you've been sitting on this mountain all night, sir."
"Mn. Isn't that what yōkai are supposed to do?"
"…" A brief silence. The young man's gaze fell upon Onikiri, then shifted away without any visible reaction. He had long since perceived that the figure before him was a demon, not a man. It meant nothing to him. He only asked: "…Just now. The grass and trees?"
"My doing," Shinji admitted directly, saving the other the trouble of guessing. The young man did not press further. He merely nodded, as if to say: I see. It's fine.
That level of composure was, frankly, not quite the reaction one would expect from a normal human. But Tsugikuni Yoriichi was never ordinary to begin with.
From what Shinji knew, Tsugikuni Yoriichi was born into a well-known landed noble family of the Warring States era. From birth, he possessed an ability called the "Transparent World", a power that could see through all things. To call it "seeing," however, was somewhat inaccurate. It was more akin to a form of "prediction."
A powerful ability that could observe all movements, both internal and external, of an opponent, constructing corresponding images within the mind. It could perceive, in an instant, the rise and fall of an opponent's lungs, the flow and contraction of their blood vessels.
Conversely, it could also grant absolute control over every movement of one's own body. He was born extraordinary. And because he was the second son, he received little attention. Fearing he would cause trouble for others, he never spoke, and was thus mistaken for a mute.
Later, simply because he inadvertently revealed his absurd, heaven-defying talent for the sword, defeating, with ease, a family swordsman who had decades of battlefield experience, the very first time he picked up a blade, he worried he would undermine his elder brother's position as heir.
And so he left the family of his own accord, living in seclusion and marrying a commoner. Unimaginably strong. Yet content with an ordinary life. This was Tsugikuni Yoriichi. So it was no surprise he could see that Shinji was a yōkai.
And it was no surprise that, with that ability called the Transparent World, he had already witnessed many anomalies. No surprise at all. But, it was clear he could not see through Shinji's existence. Otherwise, he wouldn't have asked.
Shinji spoke: "You live nearby?" Though he hardly needed to ask. This was likely where the other had been living in seclusion. The young man nodded. "In the mountains outside the city. Three years now."
"A hunter?"
"A hunter." The young man paused. "My wife is near her time. I came into the city to find a midwife."
He spoke the words with perfect calm. But the moment Shinji heard them, something in his mind jolted violently.
His wife is near her time. Came into the city to find a midwife. … Shinji remembered. Yet again, he remembered. As he had noted before, he knew the background of Tsugikuni Yoriichi from Demon Slayer.
And Yoriichi's wife and child were a pivotal link in the life of the man called Tsugikuni Yoriichi. Because while he was away from home, they would be attacked by a demon spawned by Kibutsuji Muzan. All of them would die. It was precisely this event that led to Tsugikuni Yoriichi being discovered by the Demon Slayer Corps, and ultimately becoming the strongest swordsman in its history.
That event occurred when his wife was on the verge of giving birth, and he had gone out to find a midwife. Returning home, to that. And now, standing here, it was clear that event was about to unfold.
Truly… it was better to arrive early than to arrive at the perfect moment. He had journeyed all this way, following the trail of his own Will, searching for the Demon Slayer Corps along the way.
He had never imagined, he hadn't found the Demon Slayer Corps, but he had found this progenitor of the Breathing Techniques first. This Tsugikuni Yoriichi, who, it now seemed, had already grasped the Breathing Technique, but had yet to join the Demon Slayer Corps, let alone systematize, teach, and disseminate the Breathing Techniques.
Shinji's mind began to stir once more.
"Your wife is home alone?"
"A neighbor is helping to look after her."
"How long have you been out?"
"I left before dawn. About two hours now."
Shinji calculated the time. He knew the event had yet to occur. But that window, was limited.
If demons feared the sun, then he had to make it back before sunset.
Calmly, he asked another question. "Did you find a midwife?"
"Not yet."
"Which part of town were you looking in?"
The young man tilted his head and glanced at him. A trace of confusion flickered in those deep crimson eyes, confusion over why a yōkai would care whether he'd found a midwife or not.
But he didn't refuse to answer. After all, he had been the one drawn here first, the one who had disturbed the other.
"The clinic on the north side. They said the midwife was called away for an emergency yesterday. Won't be back until today."
Shinji nodded. Then added, "There's another one, on the south side of the castle town." He had seen it when he entered the city the day before.
The young man fell silent again, studying him, as if judging whether those words were true. Then he turned and began walking toward the southern part of the city.
The motion was perfectly natural, as though he had intended to head that way all along and had simply taken a detour. After two steps, he glanced back. Those deep crimson eyes rested on Shinji.
"Are you just passing through, sir?"
"You could say that."
"Which direction are you headed?"
"No fixed direction. Just wandering."
The young man nodded. He asked nothing more. He turned back and continued toward the city. His figure gradually faded into the morning mist, his steps so steady they were nearly soundless.
Shinji remained where he was, watching that retreating silhouette. His fingers rested lightly on Onikiri's sheath. There was much he had not said. For instance, he had recognized who this person was.
For instance, he had not forgotten that the name Tsugikuni ranked among the branch families of the Hōjō clan. But this man before him had long since left the Tsugikuni house, established his own household, and lived the life of a hunter.
For instance, he had a fairly good idea of what would happen before this day was through.
But no matter how he looked at it, Shinji understood: follow Tsugikuni Yoriichi, and he would find the Demon Slayer Corps. And through them, the Nichirin Blades.
Even setting the Nichirin Blades aside, Shinji was, in truth, interested in Tsugikuni Yoriichi himself. This man, born extraordinary. In this world where so many elements had merged, what did such an existence truly represent? Shinji was genuinely curious.
So he followed. He didn't say he was following. Didn't explain why. He simply walked in the same direction, three paces behind. The young man didn't look back to ask. Two figures. One in front. One behind. Vanishing into the morning mist.