Yoriichi shook his head, confused. Was this a dream or reality? His head spun, and a chill ran down his spine.
"Am I… dead again?"
No, that wasn't possible, he thought. He had only fallen asleep on the train. Even if something tried to attack him while asleep, his body would react instantly. He would wake up.
Yoriichi turned to the wall covered with photos.
One photo showed a family of three. It looked peaceful, almost happy—but the faces were blurred, hidden. It was as if someone didn't want anyone to see them.
Is this my dream… or someone else's?
He moved away from the wall, searching the room for clues.
On a table, there was a large flat black square, and beside it a flat box that looked like stone.
"…Everything here feels so strange," he muttered.
He touched the black square. It was smooth, almost too easy to punch through if he tried. Seeing nothing, his gaze fell on the locked drawer. With a sharp push, he forced it open.
Inside were stacks of red and green papers, each with numbers—100, 50—and a tiny portrait.
Among the papers, a notebook caught his eye. A name was scrawled across it but scratched out. Two nails pinned the pages, one on top, one on bottom, as if warning anyone not to open it.
Yoriichi carefully removed the nails, closed his eyes, and apologized silently before flipping through the pages.
Many pages at the front were torn. Still, he pressed on, page by page, until he found a page with words.
At first, he couldn't understand them—they weren't in any language he knew. But slowly, the meaning came clear.
"May 5. Father abandoned my sick mother and me. He went to be with a wealthier woman…"
Yoriichi frowned but kept reading.
"June 6. Mother's health is improving. She can get out of bed."
"August 8. After leaving my father's house, life improved. Mother got better, and I found a stable income. The happiest day of my life."
It seemed like a family's story: a father abandons them, but mother and child survive, grow stronger.
"…No clues here," Yoriichi muttered. The notebook seemed like a strange diary—personal, but nothing useful.
He turned another page.
"March 3. My birthday. Mother died because…"
His pupils shrank. The lower half of the page was torn away, deliberately hidden.
What was written there? Why tear it off?
He flipped on.
"March 3. After the verdict, I inherited my father's estate because…"
"Again?" he muttered. The next page was torn into pieces. Half the book was gone.
"August 8, 2019. I became a doctor."
"2019?! What kind of diary is this?!" Yoriichi's hands trembled. A record spanning time—how could this exist?
He kept flipping, but most pages were blank… until the last one:
"July 7, 2022. I broke my foot at the hospital, recuperating at home. Discovered an interesting anime and manga…"
The lower half was torn away too. Intentional, obviously.
Yoriichi closed the notebook, staring at it in confusion. Most of the torn pages must have held important information. As of now, there were no answers.
Bang!
A sudden voice rang out. Yoriichi blinked, and everything around him turned blinding white.
A pitch-black door stood ahead, shrouded in faint black mist.
It was terrifying… yet irresistibly captivating. Danger beckoned him forward.
He took a deep breath, deciding to push the door open.
Squeak—!
"Hey, someone there?!"
A familiar voice—but not from a person. A vague, human-shaped shadow appeared.
Yoriichi tensed. No breathing technique worked. His transparent world couldn't activate. Only his natural strength remained.
"…Who are you?"
"I don't even know myself~" the shadow replied, jokingly.
Then its tone shifted. "But if you break the light on the ground, I might answer your question~"
Yoriichi looked down. A strange light covered the floor. Without hesitation, he stomped on it.
Boom! Boom! Boom!
The small space shook and split. The shadow leapt in joy. But soon, the shaking stopped. The shadow sat, lost and calm.
"There's… a second seal," it muttered.
Yoriichi stiffened. His body reacted instinctively—a warning. A true threat. His vision blurred… then, a man in a suit and top hat appeared.
"I didn't expect anyone's consciousness to reach here. Strange indeed," the man said. His voice was low, ghostly, dripping with cold darkness.
Yoriichi felt himself fading, disappearing.
"It's not over yet… seems like fate wills it so~"
"Yes, Mr. Dark," came a voice.
The man in the suit stepped toward the dark door, glancing back at the black shadow. His red eyes glinted with pride and mockery.
"Hehehe… one day, I'll escape. But not today…" The shadow laughed weirdly. "One day, I'll truly be myself."
The suited figure ignored him and walked through the dark door, leaving the small space.
Then… let's see. Who will become themselves first—me, or you?
Yoriichi snapped awake. The flames of Sun Breathing erupted from his body, burning the ropes binding his hands—though the rope entangling him and the boy didn't burn.
He frowned and quickly scanned the carriage. All the humans were gone, except Rengoku, Tanjiro, and the others.
Rengoku instinctively tugged at the rope restraining the boy in his dream, but the boy didn't wake. A fierce aura of murderous intent surrounded him.
Tanjiro, Inosuke, and Zenitsu remained in deep sleep. Nezuko appeared in Tanjiro's arms, blood streaked across her forehead, the box next to him open.
"Sixth Form: Burning Bone Sun," Yoriichi's voice was calm but firm. He didn't draw his sword. Instead, the flames of the sun flowed from his body, swirling into a vortex.
The flames fell on the ropes binding Rengoku and the others. In an instant, the ropes turned to ash, and everyone woke.
Rengoku sprang to his feet, grasped his Nichirin Sword, slapped his forehead with his free hand, and shouted, half angry, half amazed:
"So it's a ghost that can control dreams! That dream it gave me… was unlike anything I've seen!"
Flames spread along his sword, his legs flexed, and his body launched forward like an arrow. In a blink, he burst through the roof of the train.
"Go too! No one in the carriage will be hurt!" Yoriichi held the boy tightly in one arm while the other hand drew the Sun Blade, its red and white flames burning bright.
Tanjiro and the others didn't hesitate. They nodded, opened the windows, and climbed onto the roof to join Rengoku.
Outside, Rengoku had already severed Nightmare's neck, but the demon's body began merging with the train itself, flesh spreading like a living mass, threatening the passengers.
"Eleventh Form: Sun Halo Dragon—Fire Dance!"
Yoriichi swung the blade in a wide arc, flames forming a dragon. The surrounding monstrous flesh hissed and burned to ash instantly.
He tightened his grip on the boy and pushed forward, the dragon-shaped blade smashing through the train toward the control car.
Boom! Boom! Boom!
Everyplace the flames touched burned, stopping the flesh from spreading, but the passengers remained unharmed.
Inside the carriage, Yoriichi spotted Nightmare's neck through the Transparent World. He focused, readying his attack.
"The First Form: Round Dance!"
But then he noticed Tanjiro leaping from a high point. Making sure Tanjiro could finish the cut, Yoriichi shifted his stance and leapt after him.
"God of Fire, Kagura—Second Form, Blue Sky!"
Nightmare's head was severed, the train's control room came to a halt, and the back carriages still held sleeping humans.
A flash of fire appeared. Rengoku crouched, ready, shouting:
"Flame Breathing—Fifth Form: Flame Tiger!"
The fire-shaped tiger surged forward, smashing into the locomotive. With a deafening crash, the train slowed, the collapse limited to the engine. Smoke drifted away harmlessly.
Rengoku, Tanjiro, and the others were unharmed, relief washing over them.
Nearby, Yoriichi leaned against a tree, sword planted in the ground. He stared at the boy in his arms, puzzled.
"Could that dream… have affected him?"
Suddenly, a dark premonition gripped him, like an endless void devouring his life force. He scanned the surroundings, but the sense of danger seemed to come from… himself.
A figure appeared. Rengoku, Tanjiro, and the others instinctively looked over, shock and fear in their eyes.
Yoriichi felt a weight shift in his arms. The boy he'd been holding had vanished.
"Wow… the proportions are perfect, and this Blood Demon Art is amazing!"
The voice rang out, filled with pride, excitement, and eerie familiarity—like Yoriichi, but not.
The figure's gaze swept over Tanjiro and the others before settling on Yoriichi. A red glow appeared on its body, its white shirt cracking as nine long, thorned whips stretched behind it. White hair flowed down.
"I am grateful to you, human, for letting me reclaim my body."
Yoriichi's pupils shrank. He drew the Sun Blade and surrounded himself with flames, anger burning in his eyes. His usually calm face twisted into a harsh expression.
"Who are you!? Where is Kumokawa!?"
The figure didn't answer. Instead, it touched its throat, shifting its voice, while the whips behind it lashed the ground, cracking it.
"Kumokawa? The human who 'took' my body? How should I know where he is? He's probably long dead. I am the true owner of this body."
"Kibutsuji Muzan!!"