The night wind from the Entertainment District swept through the hole in the wooden wall, lifting the hem of Future Giyu's black cloak and scattering the last traces of perfume that lingered in the air.
Mushiki was still pinned to the wall, the four short daggers embedded in his limbs glowing faintly with red-gold light that suppressed his regeneration. Yet despite his wounds, he felt no pain—only the crushing weight of the man's words, echoing like a hammer against the depths of his mind.
"Complete Memory Suppression Serum…"
Mushiki repeated the words under his breath, his fingers trembling.
The serum spread slowly through his body. The fragments of memory that had long been buried under Muzan's demonic cells began to stir, breaking free from the seal that had trapped them.
In his mind, images flickered—
a young boy, Tō, clumsily swinging his Nichirin Sword in training while he stood beside him giving guidance;
and a girl in a butterfly-patterned haori, Shinobu, holding a vial of medicine and scolding him softly, "Stop getting yourself hurt all the time."
The images were faint, but his heart clenched painfully with every one.
Future Giyu watched his expression, his own eyes shadowed with understanding and regret. "Your memories weren't erased," he said quietly. "They were sealed by Muzan's mark. This serum not only blocks his control—it slowly dissolves that seal and restores everything you've forgotten."
He paused, his voice dropping lower, heavy with something that sounded like guilt. "The reason I came back… is because the future we reached was too tragic."
"Tragic?" Mushiki's throat tightened. "What do you mean?"
"An apocalypse."
Future Giyu's gaze went distant, as if he were staring through time itself, seeing the rivers of blood in that doomed world.
"After I became Mushiki, I became Muzan's sharpest weapon. When he ordered me to slaughter the Demon Slayer Corps, I obeyed. When he told me to erase a stronghold, I left nothing alive.
The first time I led a massacre against the Corps, I killed thirty-seven slayers—three of them were just children. They had only just learned how to hold a sword."
Mushiki's entire body trembled. A blinding flash of red filled his mind, echoing with the cries of children.
He clutched his head and groaned in agony.
Those weren't his memories—they belonged to the man before him—but because they were the same person, the pain was unbearable.
"Don't fight it!"
Future Giyu stepped forward and gripped his shoulder firmly. "You have to listen. These are the sins you'll commit… and the reason I'm here—to stop them."
Mushiki gritted his teeth and forced himself to nod.
Future Giyu loosened his grip and turned toward the window. The red lanterns outside flickered, their glow trembling across his face.
"After that, the Hashira began to fight back," he said, his voice edged with bitter sorrow. "Iguro Obanai, the Serpent Hashira—he noticed something was wrong with me. He secretly worked with Shinobu, hoping to restore my memory.
But before they could act, Muzan discovered Iguro's plan. He injected every Upper Moon with Blood Bombs—detonations that would ignite the blood of anyone who dared to betray him."
He stopped, his hands unconsciously gripping the edge of his cloak, knuckles white.
"I was there when Iguro died," he said softly. "Muzan made me watch. His body exploded from within before he could even finish his last sentence. His eyes... they weren't filled with hatred. They were filled with pity.
Pity that I couldn't remember who I was."
Mushiki's breath quickened. In his mind appeared the vague image of a man with bandages around his mouth, quiet and solemn, always standing in the corner. The memory ached, deep and raw.
"The one who truly woke me up," Future Giyu said, his voice cracking for the first time, "was Shinobu."
He paused, swallowing hard. Emotion shook through every word that followed.
"That day, Muzan led us in a final assault on the Demon Slayer Corps headquarters. I cut down Kanae with my own blade, wounded Muichiro, and was about to kill Tanjiro… when Shinobu charged at me.
Her Nichirin Sword was special—it held a full dose of the Complete Memory Suppression Serum hidden inside its blade."
He pressed a hand to his chest, as if he could still feel the blade that had pierced him.
"She used all her strength to drive the sword through my heart, injecting the serum directly into my body. I can still see her face—blood running from her mouth, but she smiled.
She said, 'Giyu-san… please wake up. Everyone's waiting for you.'"
He lowered his head, voice breaking. "And then… I pulled out the sword and cut off her head myself."
"No!"
Mushiki roared, his voice echoing through the ruined corridor.
His mind flooded with scenes—Shinobu's smiling face as she handed him a vial, saying, "This will help you"; the image of her falling in a pool of blood, her head rolling across the ground, her eyes still open—filled with hope.
The memories stabbed into his mind like knives, tearing through him until his whole body shook.
He didn't know why it hurt so much. He couldn't even remember her clearly.
But it felt like losing the most precious person in the world. His chest burned as if it had been ripped apart.
"This is your future," Future Giyu said softly, but every word hit like iron.
"After Shinobu died, I woke up. But by then… everything was gone.
Kanae was dead. Muichiro was dead. Sanemi was dead. Gyomei was dead.
All the Hashira… were killed by me and the other Upper Moons.
The Corps headquarters was burned to ash—only ruins remained."
He turned back toward Mushiki, his expression hollow, his eyes filled with despair.
"When I finally reached the headquarters, I found only the new Master—a boy, the last survivor of the Ubuyashiki family.
He was hiding in a sealed chamber, clutching Oyakata-sama's will and three vials of medicine.
The old Master had already foreseen everything. He left instructions—one vial to turn me human again, and two to weaken Muzan—to age his body rapidly and suppress his regeneration.
He told the boy to give them to me… and send me to end Muzan once and for all."
Future Giyu's hand clenched tighter. "It took me three years.
I killed every Upper Moon. Akaza fell by my Sun Breathing blade. Kokushibo died after I wore him down, blow by blow…"
All the other Upper Moons fell beneath my blade. In the end, I found Muzan, used the two vials of medicine to weaken him, and after fighting for three or four hours, I killed him under the sun."
"At first, I intended to die beneath that sunlight too—after all, I was still a demon."
"But I didn't die. I survived. I conquered the sun and became the first demon unburned by its light."
"I think… it was because I had mastered Sun Breathing."
"But even then, I still chose to inject the medicine that would turn me human again. I hoped it would work. After the battle with Muzan, the demon cells inside me were almost completely gone… so I did become human again."
Future Giyu's voice grew hollow, like he was telling someone else's story. "I killed Muzan. I won the war. But everyone I cared about was gone.
The new Master fell sick and died. The Kakushi disbanded. The world became silent. Only I remained.
I stood before the ruins of the Corps' stronghold, before the rubble of the Butterfly Mansion, before Shinobu's grave… and I finally understood—
I didn't win. I lost everything. I didn't save anyone."
Tears slipped down Mushiki's cheeks before he even noticed. He didn't know why he was crying. His chest just felt hollow, as if something vital had been carved out of him.
He looked at Future Giyu—at the man who shared his face yet carried the sorrow of an entire world—and suddenly realized something. The future tragedy wasn't fixed. He still had time to change it.
"But… I killed Kyojuro…"
Mushiki's voice was hoarse, trembling slightly. In his mind, he saw the moment he struck down Rengoku Kyojuro—flames fading in the darkness.
Future Giyu stepped forward, his eyes filled with quiet resolve. "Right now, the Flame Hashira isn't dead yet.
In the future I came from, I still met him in the final battle. That means Tamayo-san must have saved him.
Tō and Tanjiro are badly wounded, but alive. Shinobu is still working in her lab. Kanae and Muichiro are alive too.
The Demon Slayer Corps hasn't fallen yet. There's still hope.
If you can awaken your memories now and stay by Muzan's side unnoticed, gain his trust, and uncover information about the Blue Spider Lily, we can stop this future from happening."
He raised his hand and pulled the daggers from Mushiki's limbs.
The red-gold light faded, and Mushiki's wounds began to heal slowly.
"The serum is working. Over the next few days, you'll start remembering more.
Listen—don't let Muzan notice any change in you. Keep playing the part of 'Mushiki.'
I'll help you from the shadows, sending you what you need until your memories are fully restored."
But then, Future Giyu's body began to fade, turning translucent as if dissolving into the air.
His face remained calm. "The time-space connection isn't stable. I can't stay here long.
Remember—your choices decide everyone's fate.
Don't make the same mistake I did. Don't wait until everything is gone to regret it."
"Wait!"
Mushiki lunged forward and caught his hand.
"What should I do? If I remember everything but lose control of my body—what then? What if Muzan finds out?"
Future Giyu placed a hand on his shoulder. His eyes were steady, filled with unshakable trust.
"You won't. Because you still have people you want to protect.
Those memories, those feelings—they'll help you fight back against Muzan's control.
Believe in yourself… the same way I believed in the future me who killed Muzan."
With that, his body turned completely transparent and vanished into the air.
Only one thing remained where he had stood—a small, gleaming serpent scale.
It was Iguro Obanai's keepsake, the one Future Giyu had carried with him to the end.
Mushiki bent down, picked up the scale, and held it tightly. The faint warmth that lingered on it spread through his fingers, easing the haze in his heart.
He walked to the window, staring into the deep night. In his mind, fragments of memory flickered again—becoming clearer, sharper, more alive.
He gripped his Nichirin Sword and turned toward the corridor.
He would return to the Infinity Castle. He would continue his act as "Mushiki."
But this time, his purpose was not to serve Muzan.
It was to protect those he wanted to protect—to change the future that had once ended in despair.
In the hallway, Ayuki still cowered in the corner, trembling in fear.
Mushiki—no, Giyu—walked up to her, paused, and said quietly, "Go. Leave the district. Find somewhere safe to live. Don't come back."
Ayuki blinked in surprise, then nodded quickly, scrambling to her feet and hurrying down the stairs into the night.
Giyu watched her disappear into the darkness. A faint warmth flickered in his chest.
He knew—this was the first step toward changing fate.
Ahead lay Muzan's watchful eyes, the suspicion of the Upper Moons, the battle between his returning memories and the demon blood inside him.
But he was no longer afraid. Because he knew that the future version of himself had already proven it—
As long as there is someone to protect, there is no darkness that cannot be overcome.
He turned, walking toward the direction of the Infinity Castle.
The black hem of his kimono rippled in the night, like a shadow streaking through the haze of the red-light district, slicing apart its stillness.
His steps were firm. His gaze, unshaken. Because he knew—
Behind him stood the hope of the Demon Slayer Corps, the people he wanted to protect.
And ahead of him lay the battlefield where destiny could be rewritten—his path of redemption as Tomioka Giyu.
The wind still blew, the red lanterns still swayed, but that night in the Entertainment District seemed a little brighter—
A faint light, fragile but real, shining just enough to guide the way forward, enough to give a hopeless future a chance at hope.