Steam hissed from the iron beast as Yoriichi and Rengoku stepped aboard the Mugen Train. The warm glow of the lamps inside wrapped the carriage in a golden haze, a sharp contrast to the cool bite of the night air outside. The faint aroma of tea and freshly cooked rice drifted through the narrow aisle, mingling with the steady rhythm of wheels rolling over steel.
Passengers spoke in hushed voices, their words blending into a low, constant murmur. The occasional burst of laughter from a group at the far end seemed almost out of place, fragile against the weight of the mission the two Demon Slayers carried. None of these travelers could imagine what truly moved in the dark.
Rengoku made his way to a seat beside the window, his posture immaculate, broad shoulders squared with the confidence of a man certain in his strength. The flickering lamplight caught in his golden hair, turning the red tips to smoldering embers.
Yoriichi slid into the seat opposite him, his movements fluid, almost soundless. His gaze drifted across the compartment—not searching for anything in particular, but absorbing every detail: the glint of the polished brass handrails, the faint sway of hanging lanterns, the way the shadows pooled in corners. To him, this moving fortress of steel was as alien as a dream.
Rengoku raised a hand to wave down the attendant with the same enthusiasm he carried into battle.
"Two bentos, please!"
The attendant bowed politely and returned moments later with neatly wrapped boxes, still warm to the touch. Rengoku accepted them with a grin, the savory scent already teasing his senses. Without the slightest hesitation, he untied the first cloth, revealing a meal so perfectly arranged it looked like a small celebration in a box.
The first bite vanished almost before the lid had fully settled on the table. A rush of savory flavor hit his tongue, and his entire expression ignited with unrestrained delight. Then, with all the force and clarity of a victory cry, his voice rang through the carriage:
"UMAI!"
The sound carried down the aisle, startling a few nearby passengers and drawing curious glances from others. One elderly man blinked in surprise over his newspaper, while a child peeked up from behind her mother's sleeve, eyes wide.
Rengoku didn't notice—or perhaps he simply didn't care. The joy of the meal demanded celebration. He took another generous bite, his chopsticks moving with eager precision, and again his voice boomed, even louder than before:
"UMAI!"
The word rolled like a wave of warmth through the otherwise quiet carriage. A few passengers exchanged amused looks, some smiling faintly, as if the outburst had somehow made the night feel less cold.
Across from him, Yoriichi remained still, watching without a word. His face betrayed no obvious reaction, but deep in his calm gaze was the faintest spark—an almost imperceptible flicker of amusement, as though this loud, burning presence across the table was both strange and unexpectedly welcome.
Between bites, Rengoku's tone shifted from the warmth of conversation to the steadiness of a commander sharing vital intelligence.
"Reports say forty passengers have gone missing," he said, lowering his voice slightly. "Signs of demon activity were found on board. That's why we were sent to investigate."
Yoriichi listened without interrupting, his gaze fixed on Rengoku, though his mind traced the meaning behind each word. Forty lives, taken silently in a confined space such as this… it spoke of a predator with cunning and patience. He did not speak, but every syllable settled in him like a stone dropping into still water.
Moments later, the soft clink of metal on metal announced the arrival of the ticket collector. The man moved with mechanical precision down the aisle, his uniform crisp, his footsteps measured. He paused at each seat to punch tickets with a small, polite bow.
When he stopped before them, Yoriichi's eyes lingered—not on the man's face, but on the subtle things: the stiffness in his posture, the faint unevenness of his breathing, the way his scent carried a thread of something unnatural beneath the smell of pressed cloth and ink. To any other passenger, he looked entirely ordinary. But to Yoriichi… he was too ordinary. Unnaturally so.
The collector moved on, vanishing into the next carriage.
Then—
A sudden ripple of movement at the far end of the car. The air turned cold. From the shadows between the seats, a demon unfolded itself—limbs twisting in unnatural angles, its eyes wild with hunger. The creature let out a guttural hiss, snapping heads around in shock.
Gasps and screams filled the compartment. Passengers shrank back into their seats, some frozen in terror, others clutching their loved ones.
Rengoku's hand shot toward his sword, but the demon was already lunging—claws gleaming under the dim lamplight.
Clang.
A streak of silver split the air. For an instant, the world seemed to still, caught in the silent aftermath of the strike.
Yoriichi stood where he had been a moment before, but his blade was already returning to its sheath. The demon's head slid from its shoulders with a faint, almost confused twitch. Ash scattered into the air before most of the passengers could even register what had happened.
The cries subsided into stunned silence. A few travelers blinked in disbelief, as if they had imagined the danger entirely.
Rengoku broke the quiet with a broad grin, his voice carrying the same fire as always.
"Your skill is extraordinary," he said with genuine admiration. "With you here, I think we can finish this mission with ease!"
But elsewhere, in the shrouded belly of the train, another scene was quietly unfolding—one far removed from the murmured conversations and rattling wheels.
The ticket collector, moving between carriages with his neat stack of stubs, froze as something emerged from the darkness ahead. A pale, skeletal hand slipped into view from the shadows—its skin stretched tight over bone, claws glinting in the faint light. The fingers curled slowly, deliberately, until they hovered mere inches from his chest.
His breath hitched. The faint scent of rust and something foul filled his nostrils.
"Please… leave my family out of this," he whispered, desperation cracking through his voice. "I'll… I'll do whatever you want, just spare them."
The hand did not strike. It simply lingered, an unspoken promise of doom.
Then it came—an unseen tide of pressure, heavy and cold, pouring over him like a deep ocean swell. It pressed into his bones, sank into his lungs. His vision wavered. The world blurred. His knees buckled.
The collector's eyelids drooped against his will. He swayed once… and collapsed like a marionette with its strings cut. His breathing slowed, shallow and ragged, until it stopped altogether.
Somewhere, in the still air of the carriage, the faintest echo of a chuckle lingered.
And in that same heartbeat—
Yoriichi felt it.
It began as a ripple in his senses, a distortion in the world that only his instincts could read. Then, all at once, the wooden floor beneath him melted away, the sound of the train's wheels vanished, and the warm lamplight collapsed into darkness.
When the shadows lifted, he was standing barefoot on sun-warmed earth.
The wind carried the scent of pine. Birds called in the distance. The air was so clean it almost hurt to breathe.
Before him, a voice—soft, familiar, weighted with years—spoke his name.
"Yoriichi…"
His chest tightened. He knew that voice.
"Michaekatsu…"
His brother stood there—not the demon he had become, but the man of his memory. The lines of his face were untouched by time. His eyes held neither malice nor madness, only the steady light of the boy Yoriichi had once loved.
Behind him stood their childhood home. Smoke curled lazily from the hearth. The door slid open—
And Uta stepped into the sunlight.
Her hair gleamed, her smile was gentle, and her hands rested protectively over the swell of her stomach. She was alive. She was waiting for him.
Yoriichi's steps faltered. For a single heartbeat, he could believe this was real. The ache in his chest throbbed with the memory of all he had lost. He could almost feel the warmth of Uta's hand, hear her soft laugh.
But then—
The light around her wavered. The air grew thick. The birdsong faltered mid-note.
And in the stillness, he heard it: the faint, steady drip of blood.
His eyes sharpened. The world around him was flawless—too flawless. Shadows clung in the wrong places. His heartbeat, slow and steady, was the only thing that felt alive.
"This is…" he murmured, the sorrow in his tone sharpening into steel. "…a Blood Demon Art."
The figure of Uta stepped toward him, smile unchanged—but her shadow writhed unnaturally on the ground. It stretched into hooked claws, inching toward his feet.
Yoriichi moved.
His hand came up, and with a sudden surge of will, he shoved the false image away. The dream warped like shattered glass, fragments of sky and sunlight falling away into nothingness. The figure stumbled back, her smile twisting into a snarl—eyes turning the crimson of a predator.
She lunged, claws outstretched, the false sunlight glinting off them like shards of glass—but Yoriichi's strike was swifter than thought. His palm met her chest in a single, precise movement, driving her back with a force that shattered the stillness of that fabricated world.
The dream shuddered. The air fractured with sharp cracks, like ice breaking over a frozen lake. The figure that had worn Uta's face tumbled into the empty void beyond, her expression twisting into something monstrous before her form dissolved completely.
The false sky above him sagged and tore, bleeding into darkness. Light peeled away in ribbons. The scent of pine vanished. The warmth on his skin turned cold.
And then—
Reality slammed back into place.
The rattle of wheels thundered beneath him. The metallic scent of iron, coal, and steam flooded his senses. The walls of the Mugen Train were solid once more, lit by the steady glow of the carriage lamps. Passengers shifted uneasily in their seats, oblivious to how close their dreams had been to becoming graves.
But the Blood Demon Art slid off Yoriichi's mind like water over polished steel. No dream could take hold of him—no illusion could root itself in the unshakable ground of his spirit. His heart beat in a state of pure, unbroken clarity, free of greed, fear, or desire. Yoriichi had long since abandoned the self; his will flowed only toward the protection of others. In that selfless state, there was no opening for the demon's art to exploit—only the calm, endless sky of a warrior who had walked centuries without faltering.
Across the aisle, Kyojuro Rengoku sat slumped in his seat. His usually unshakable presence was unnervingly still, a faint trace of tension tightening his brow. His breathing was steady, but deep—trapped in the clutches of an unnatural slumber.
Yoriichi stepped forward, each footfall soundless. For a brief moment, he simply observed his companion, the faint flicker of lamplight reflecting off his calm yet intent gaze. Then he reached out and laid a steady hand on Rengoku's shoulder.
"Rengoku," he said quietly, his voice carrying the weight of absolute certainty. The Flame Hashira stirred but did not wake.
Without hesitation, Yoriichi gripped his shoulder firmly and gave a sharp, controlled shake. Rengoku's eyes snapped open, confusion flashing only for an instant before focus returned to them like a spark catching flame.
"There is a Blood Demon Art at work here," Yoriichi told him, his tone even but edged with urgency. "The demon is weaving illusions—placing its prey in dreams to render them helpless. It nearly claimed the ticket collector's life, and it will try for every passenger aboard."
Rengoku's gaze hardened instantly, his grip tightening on the hilt of his blade. "Hmph. A coward's tactic. But one we'll cut through all the same."
Yoriichi's eyes narrowed slightly, his focus 'see through the world' piercing beyond the thin walls of their carriage. "It has merged with the train itself. Its core is in the front most part of carriage."
In that moment, a violent shockwave tore through the Mugen Train, making the very steel beneath their feet tremble. The walls quivered, the steady rhythm of the wheels faltered for a heartbeat, and the lamps flickered—casting long, distorted shadows that seemed to writhe across the carriage. From the front of the train came a deep, resonant groan, not mechanical but alive—like the stirring breath of some vast beast hidden in the heart of the engine.
A pressure filled the air, cold and suffocating, pressing against the lungs of all who sat within. Passengers shifted uneasily, sensing something was wrong though unable to name it.
Yoriichi's amber eyes sharpened, his focus narrowing toward the unseen source. Rengoku's fiery gaze followed the same invisible path, the air between them taut with unspoken resolve.
Their hands moved in perfect unison—Yoriichi's fingers curling around the hilt of his katana, Rengoku's gripping his flame-wreathed blade's tsuka with unyielding strength. The sound of steel shifting in its scabbard whispered through the tense air.