The Hashira meeting had concluded beneath the tranquil sky of the Ubuyashiki estate. As the other Hashira departed in solemn silence, one figure remained behind. Kyojuro Rengoku turned, his gaze landing on the lone swordsman standing near the entrance.
Long crimson hair swayed gently in the breeze, and the soft glow of the afternoon sun caught on his hanafuda earrings. There was an air of quiet stillness about him—calm, yet vast, as if he existed outside the flow of time itself.
Yoriichi Tsugikuni.
Rengoku took a steady breath before stepping forward, his voice carrying its usual warmth and unwavering resolve.
"Yoriichi-san!"
The swordsman turned slightly, amber eyes meeting Rengoku's with quiet attentiveness. He said nothing, yet his gaze alone held a depth beyond words.
Rengoku smiled. "Kagaya-sama has asked that you accompany me on the Mugen Train mission. Fighting alongside you would be an honor."
For a moment, Yoriichi remained silent. His expression did not change, but something in his eyes shifted, as if recalling something distant, something lost.
"…I understand."
His voice was gentle yet carried immeasurable weight. There was no hesitation, no doubt—only quiet acceptance, as though he had long since learned to move where fate willed him.
Rengoku's smile brightened. "Excellent! With you by my side, we will ensure no lives are lost tonight. Come, the train awaits!"
Yoriichi studied him for a brief moment before giving a small nod. His movements were fluid, almost unreal, as he stepped forward, falling into stride beside the Flame Hashira.
Yoriichi, his calm eyes steady, nodded once. He spoke few words, but his presence was louder than speech.
As the sun dipped below the horizon, painting the sky in hues of blood and fire, the two slayers made their way toward Hamugin Station.
Just as the two prepared to board, a scream shattered the calm.
A girl no older than ten was yanked back by a clawed hand. A twisted figure stood in the open, his eyes wild, face smeared with madness. The Slasher Demon, as he was whispered in the shadows.
"Back off, or she dies!" the demon snarled, baring blood-stained teeth.
Rengoku reached for his sword instinctively, but before even he could act—clang—a flash of steel tore through the air. Yoriichi had moved. The motion was a blur. His blade, as graceful as moonlight, had already swept through the demon's neck.
The girl dropped to her knees, unharmed, as the demon's head rolled with a look of disbelief.
Rengoku blinked in awe, his sharp eyes wide with admiration as he watched Yoriichi lower his blade, the air still humming from the sheer speed of his strike.
"Your swordsmanship… it's beyond comprehension," Rengoku said, stepping forward with a grin that burned as brightly as his flame. "The way you moved—so precise, so swift—I could barely follow it with my eyes. That kind of mastery… it's the strength of a Hashira, without a doubt!"
Yoriichi sheathed his blade in silence.
Without another word, they stepped aboard the waiting train.
Kyojuro Rengoku stood beneath a twisted rail arch, his haori torn and singed, but his spirit unshaken. The dying light of the day painted gold across his face and hair—flames silhouetted against the dimming sky.
A sharp gasp escaped the bento lady's lips.
"…Shinjuro…?"
Kyojuro turned, brows raising slightly. An elderly woman stood there, her eyes wide and glassy. She was wrapped in a shawl, clutching her grandson close with one hand. Her other trembled slightly, reaching toward him.
Kyojuro smiled warmly. "Pardon me, madam. I believe you may be mistaking me , he was my father."
They boarded together, the train slowly beginning its journey into the night.
Inside, warm light bathed the interior of the train. Passengers relaxed, unaware of the danger that slithered beneath the floorboards.
Rengoku sat by the window, a bento box in hand—neatly packed and piping hot. Without hesitation, he opened it and took a large bite.
His eyes lit up.
"UMAI!!" he declared, loud and clear, causing a few nearby passengers to flinch in surprise.
Another bite.
"UMAI!!"
Yoriichi sat quietly across from him, observing with calm curiosity as Rengoku devoured the food like a man with nothing but joy in his heart.
"This food is delicious!" Rengoku beamed. "No matter the mission, a good meal keeps the flame burning strong!"
Yoriichi's lips twitched slightly—a flicker of amusement behind his stoic gaze.
But the warmth was short-lived.
A subtle shift—like a breeze through a closed room—swept over them.
They had handed in their tickets moments ago… and something changed.
The train groaned faintly. Darkness seeped in at the edges of vision. Spell-casters, hidden among the passengers, quietly moved to connect threads to their targets. In silence, they placed them into enchanted dreams under the command of Enmu, Lower Rank One.
Rengoku slumped gently in his seat, still smiling as he drifted into a deep, peaceful dream.
Yoriichi, however, did not fall.
His senses pierced the veil of illusion before it could take hold. The Blood Demon Art triggered no slumber in a man whose will had walked through centuries of death and battle.
Within the false dream, he drew his katana—and slashed.
He awakened instantly.
The train interior twisted—hands with scripture-scarred skin burst from seats and walls, reaching toward passengers. A sickening voice filled the air:
"You'll all dream sweetly… forever…"
"Blood Demon Art," Yoriichi muttered, standing.
"Sun Breathing, Sixth Form—Burning Bones, Summer Sun!"
A brilliant arc of fire scorched the train's interior as his blade sliced through the emerging hands, incinerating them in a flash of golden heat. Flames licked through the corridor, but left the passengers untouched.
Further back, Rengoku stirred, eyes snapping open as the dream dissolved.
"A Blood Demon Art-induced sleep technique…" he growled. "Enmu!"
Together, they moved—cutting through car after car. Yoriichi's sword was a force of nature. Rengoku followed with his own roaring flame, protecting passengers and slicing through the spreading curse.
Then, Yoriichi saw it.
With the Transparent World, his gaze pierced the train itself. His voice was sharp and low.
"The demon has merged with the train. The head is in the engine."
Rengoku nodded without hesitation. "I'll guard the people. Go!"
With a single step, Yoriichi blurred into motion.
The train groaned beneath him as he moved—his feet barely touching the roof, each stride faster than the wind that screamed through the night. Cloaked in silence, he ran with the grace of a shadow and the speed of a blade drawn in the blink of an eye.
His eyes never wavered.
The coaches whipped past behind him, one after another, until he reached the front.
He leapt lightly, landing before the engine—where the heart of the corruption lay.
A grotesque, pulsating mass of flesh twisted and throbbed, fused with metal and fire. Pipes twitched like veins, steam hissed through open wounds of iron. The stench of blood and bile filled the air.
There, embedded into the engine, was the demon's head.
"Sun Breathing, Second Form—Clear Blue Sky!"
His blade spun in a perfect arc—blinding, graceful, absolute. In one clean sweep, the engine was severed, Enmu's true body cut in two.
The demon screamed—and then silence.
CRASH.
The train, now powerless, derailed. Carriages flew, metal shrieked, and wood shattered as the Mugen Train collapsed beside the forest.
Smoke and ash filled the air.
Yoriichi and Rengoku—though scratched and bruised—were already pulling survivors from the wreckage. Slayer reinforcements arrived, guided by crows that had witnessed the fall.
Rengoku stood amid the chaos, his bright eyes scanning the scene.
Night gave way to moonlight and wreckage.
The once-mighty Mugen Train lay in pieces across the forest floor, its carriages twisted and scorched, like the coiled remains of some great beast slain in battle. Steam hissed weakly from ruptured pipes. Embers flickered in the grass. The forest itself stood still, as if holding its breath.
Survivors groaned, dazed and injured, crawling free or trapped beneath shattered beams and broken metal. Some cried for loved ones. Others simply stared at the sky in disbelief.
Through the wreckage moved two shadows—neither shaken, neither slowing.
Yoriichi Tsugikuni, his expression unreadable, lifted a heavy wooden beam with one hand and pulled a child from beneath it with the other, moving as if the weight was nothing.
Kyojuro Rengoku, flame still burning bright in his eyes despite the exhaustion in his limbs, offered his hand to a bleeding man, hoisting him gently onto his shoulder. "Hold on, friend," he said. "You're safe now."
They moved without rest, like twin beacons—sunlight and fire—against the lingering dark.
Before long, the sky was filled with the flutter of wings. Reinforcements arrived, guided by the cries of crows who had witnessed the fall. The new Demon Slayers, some young and shaken, froze at the sight before them: wreckage beyond recognition, and at the center of it, two figures still standing tall.
"Over there! Begin triage!"
"Get stretchers! That one's still breathing—go!"
The slayers fanned out, bringing order to chaos, tending to the wounded, securing the perimeter. A medic offered to treat Rengoku, but he waved them off.
"There are still passengers to recover. Help them first."
Nearby, Yoriichi paused as he cradled a child in his arms. The moonlight bathed his face, illuminating the soft sorrow in his eyes—eyes that had seen too much, across too many lifetimes.
Rengoku stepped beside him, his breath now heavy, but steady.
They stood in silence for a moment, watching as hope slowly returned to the eyes of the survivors. Children were reunited with parents. Injured civilians clutched blankets offered by slayers. The forest echoed not with screams, but with murmurs of relief.
And so, beneath the fading stars, flame and sunlight stood watch over the wreckage—guardians against the dark.
No words were needed between them.
In that moment, they were more than swordsmen.
Passengers were protectors.