The station was alive with smoke and hissing steam, metal shrieking against metal as the iron serpent loomed ahead—Mugen Train. Tanjiro stepped onto the platform alongside Zenitsu and Inosuke, the weight of Kagaya's letter pressed against his chest like a second heart.
The locomotive stood still for now, yet there was a tension in the air, a stillness that screamed louder than any engine. They boarded cautiously, eyes scanning the quiet corridors lit by flickering lanterns.
Inside, seated like a flame that refused to dim, was Kyojuro Rengoku.
"Delicious! Delicious!" he beamed with unwavering spirit, a stack of bentos vanishing before their eyes. Tanjiro bowed respectfully.
"You must be Tanjiro Kamado. I've heard of you. Let's ride this train to victory!" Rengoku's voice burned with confidence.
They exchanged brief tales—of breathing styles, of Nezuko, of Muzan. The Flame Hashira's kindness was as strong as his sword arm. And when the train whistled its final call, they were off.
But they weren't alone.
Enmu, Lower Moon One, smiled beneath the train's floor, whispering sweet promises into the dreams of the conductors. His blood-fueled plan had begun.
Passengers fell asleep—soft, one by one. Tanjiro, Inosuke, Zenitsu, and even Rengoku collapsed into dreams not their own.
Tanjiro's dream was gentle.
His family was alive. Smiles, warmth, laughter. But something was wrong—he knew it wasn't real. Tears welled as he turned from them, staggering through a dream he didn't want to leave. A haunting voice echoed through the void:
"To protect… you must sever it."
His sword flared. He cut his own neck.
Reality returned like fire.
The train shook violently. Demonic vines writhed from the walls, passengers shrieked. Enmu's body had fused with the train itself. A grotesque parasite of machinery and flesh.
"Rengoku-san!" Tanjiro cried.
Rengoku was already mid-strike, slashing car after car to protect passengers. His flames burned through Enmu's cursed flesh. Zenitsu, even in sleep, moved like lightning to guard the women and children. Inosuke, his wild instincts keeping him sharp, tore through the enemy like a beast unleashed.
Tanjiro and Inosuke reached the train's head where Enmu's neckbone—his true weak point—throbbed like a living heart.
"Inosuke, I'll distract it—!"
"Save the yelling! Let's kill this train worm!"
Their swords danced in tandem. With a scream and a final slice, Tanjiro drove his blade into the core.
Silence.
Then—
A crash.
The wreckage of the train lay twisted in the forest. But the battle was far from over.
He arrived.
A demon stepped forth from the shadows. Not Enmu. Far stronger.
Akaza. Upper Moon Three.
Power surged from his body like a blood moon rising.
"Come, Flame Hashira. Let us dance in death!"
Rengoku stepped forward, unshaken. "I refuse to let anyone here die. My flame shall never waver."
The clash was beyond words. Fists against flame, martial fury against sword precision. Rengoku fought with every ounce of strength, his body breaking, his spirit unbending.
Tanjiro, wounded, could only watch—his throat dry with helpless awe.
"Set your heart ablaze!"
Rengoku's voice echoed like a prayer. His body moved even as his vision blurred, his muscles torn. But Akaza was too powerful.
A final blow. A pierced gut. Yet Rengoku stood. He held Akaza in place as the sun began to rise.
"Your kind fears the dawn," he whispered, blood staining his lips.
Akaza tore himself free and vanished into the forest, fleeing the sunlight like a coward.
Tanjiro hurled his sword after him, screaming tears and fury. "You ran! You lost to someone stronger than you!"
Rengoku fell to his knees, smiling.
He spoke of his mother. Of living with honor. Of protecting the weak.
Then… silence.
The flame went out.
But not the fire.
Not in Tanjiro's heart.
Not in Zenitsu's, Inosuke's.
Not in anyone who watched him burn so brightly.
The Flame Hashira had passed… but his legacy had only just begun.