The One Punch Man (a.k.a Saitama) in Demon Slayer

The wind carried an eerie stillness through the forest. Tanjirou clenched his sword tighter, his breath steady but his heart uneasy. Something was coming—something powerful.

The Demon Slayers stood alert, scattered across the clearing. Giyuu rested his hand on his katana, his cold gaze fixed ahead. Shinobu tilted her head slightly, her usual playful smile absent. Even Inosuke, always eager for a fight, stayed unnaturally quiet.

And Saitama? He just stood there, scratching his head.

"Man, I was hoping for a longer break," he muttered.

Suddenly—BOOM!

A shockwave blasted through the trees, ripping them from their roots. The sky darkened as a crimson mist slithered through the air, carrying a pressure so heavy that the younger Demon Slayers nearly fell to their knees.

Then, from the shadows—he stepped forward.

Mizan.

But he wasn't the same.

His body, once human-like, had undergone a grotesque transformation. His skin pulsed with black veins, and his eyes burned crimson-red with golden pupils—resembling Muzan's, but even more sinister. His aura twisted the air around him, as if reality itself feared him.

Tanjirou gasped, feeling something deep in his soul—this wasn't just any demon.

"What… is this?"

Mizan smirked, cracking his knuckles. "You should feel honored. You're about to witness the true evolution of a demon."

The pressure intensified. Giyuu moved first, flashing forward with Water Breathing: Seventh Form! His blade sliced through the air—but stopped inches away from Mizan's neck.

An invisible force repelled him, sending Giyuu skidding backward.

"What?!"

Mizan chuckled. "Did you think the same old techniques would work on me?"

Zenitsu was already trembling. "O-Oi, I don't think we're ready for this."

But before anyone could react—

Saitama moved.

In an instant, he was standing right in front of Mizan. Their eyes met, and for the first time, Mizan felt something foreign.

Something he hadn't felt in a long time.

Fear.

Saitama stared at him blankly, then raised a fist. "You talk too much."

BOOM!

The force of the punch shattered the ground, sending shockwaves across the entire mountain. Trees were uprooted, boulders were obliterated, and the night sky split apart from the sheer impact.

A crater formed where Mizan had been standing.

Dust and debris filled the air.

Silence.

The Demon Slayers stared, stunned beyond words. Had it ended in just one punch?

But as the dust settled… a shadow rose.

Mizan was still there.

Bruised. Injured. But not dead.

He slowly grinned, his wounds healing almost instantly.

"…Interesting."

Saitama blinked. "Huh. You're still alive."

Mizan laughed. A deep, echoing laugh that sent chills down everyone's spine. His aura flared up, stronger than before.

"I see now. You… are not human."

Saitama sighed, rolling his shoulders. "Guess this might take two punches."

The battle was just beginning.

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End of Chapter 88.

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