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

The cozy ramen shop's warm atmosphere shattered in an instant.

A chilling breeze swept in as the door creaked open, and every Hashira instinctively reached for their weapons. The chef, who was just about to bring out more side dishes, froze in place, beads of sweat dripping down his face.

Standing at the entrance, dressed in a sleek black suit, was Kibutsuji Muzan. His crimson eyes glowed softly in the dim light of the shop, and his pale skin seemed almost ghostly against the backdrop of the rising sun.

"Eating ramen together so peacefully…" Muzan's voice was smooth, like silk brushing against steel. "I almost didn't recognize you all without your swords drenched in blood."

The Hashira were already moving.

Rengoku's hand slammed down on the table, flames flickering at his fingertips.

Sanemi's veins bulged with fury.

Giyuu stood silently, his grip tightening around his blade.

Shinobu's smile sharpened into something lethal.

Mitsuri — still holding chopsticks — dropped them, her appetite vanishing instantly.

But it was Saitama who reacted… in his own way.

"Can you move?" Saitama said bluntly, rubbing his stomach. "I need to use the bathroom."

The room went silent.

Muzan blinked, momentarily thrown off by the sheer casualness of the bald man in the cape.

"...Excuse me?" Muzan narrowed his eyes.

"Too much ramen." Saitama stood up, patting his belly. "Gotta go."

"DO YOU EVEN KNOW WHO I AM?!" Muzan's voice sharpened, his patience thinning.

"Yeah." Saitama yawned. "Some Michael Jackson-looking demon, right?"

The Hashira collectively gasped.

"WHAT DID YOU JUST SAY?!" Muzan's voice shook the walls, his hair bristling with fury. "You dare compare me to—"

Before he could finish, Saitama was already walking past him toward the bathroom.

"Hold that thought, Jackson. Nature calls."

Muzan's eye twitched violently. "You insufferable—!!"

But before Muzan could strike, Rengoku's flame sword slashed toward him, and the battle erupted.

---

Hashira vs Muzan — Round One

Rengoku's flames roared like a wildfire, colliding with Muzan's slicing blood whips. The small ramen shop shattered instantly, flames and demonic energy blasting through walls and sending bowls flying into the sky.

Sanemi, blade gleaming in the sunlight, leapt at Muzan from above, wind pressure cutting the air itself. "Die already, you bastard!!"

Mitsuri's Love Breathing followed right after, her elegant strikes weaving through the chaos like a dance.

Giyuu, silent and focused, appeared behind Muzan in a flash — his Calm Water Slash aiming directly for Muzan's neck.

Shinobu stood back, analyzing every movement, already planning her venomous counters.

---

Meanwhile, in the bathroom…

Saitama sat on the toilet, chin resting on his hand, completely unfazed by the explosions and screaming outside.

"Shouldn't have had that extra spicy miso," he muttered.

The wall beside him exploded, a stray blood whip tearing through the wood, barely missing his head.

Saitama glanced at it.

Sighed.

Flushed.

And stood up.

---

Muzan's Realization

The fight raged on, but something unnerved Muzan. The Hashira were strong, but there was no fear in their eyes today. Even as they fought desperately, even as they bled, they weren't trembling like before.

Because in the corner of his eye…

He saw him.

Saitama stepped out of the destroyed bathroom, cape fluttering in the morning breeze, his expression as blank as ever.

"Okay, ready." Saitama cracked his neck.

Muzan stared. "What are you?"

"Just a guy who wanted some ramen." Saitama clenched his fist. "But you ruined my meal."

The ground trembled beneath his feet.

Muzan felt something he hadn't felt in centuries.

Fear.

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To Be Continued…

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