Chapter 11: Saitama's First Mission (And It’s Already a Disaster)

The sky was painted in deep hues of crimson as the sun dipped below the horizon. Saitama sat on the engawa, munching on a rice ball that Tanjiro had handed him, eyes half-closed in boredom.

"This world is kinda quiet," he muttered. "No monsters suddenly attacking the city. No cyborg guys trying to fight me. Just swords and demons…"

"You sound disappointed," Zenitsu said, peeking from behind a pillar. Ever since the Hashira Meeting, Zenitsu had been keeping his distance from Saitama. The bald head, the broken sword incident, and the casual godlike attitude — it was too much for his anxiety to handle.

"I thought there would be more action." Saitama took another bite. "I came here because that shadowy guy said there were strong demons, but… they're kinda weak."

Tanjiro smiled nervously. "Well, you did defeat an Upper Moon in one punch, so I guess your standards are… different."

Suddenly, a Kasugai crow swooped down, landing dramatically right on Inosuke's head.

"Gah! Get off me, you stupid bird!" Inosuke swatted at it.

"Urgent! Urgent! Upper Moon sighted! South Village under attack! All nearby Demon Slayers, mobilize immediately!"

Tanjiro's face turned serious. "That's close by! We need to move now!"

Zenitsu's knees were already shaking. "A-Another Upper Moon?! But we barely survived the last one!"

Saitama stood up, brushing off rice grains from his suit. "Upper Moon, huh? Maybe this one's more fun."

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The trio and Saitama sprinted through the forest, leaves crunching beneath their feet. Tanjiro led the way, nose twitching as he caught the faint scent of blood mixed with something strange — like rotting flowers.

"Be careful, Saitama-san," Tanjiro warned. "Upper Moons are extremely dangerous. They can regenerate faster than lower demons, and their Blood Demon Arts are—"

Before Tanjiro could finish, a tree exploded in front of them. Out stepped a demon wrapped in long, twisting vines made of flesh, its skin dark green with glowing red eyes.

"Lower Moon Two," Tanjiro whispered in horror. "Why is a Lower Moon here? I thought it was an Upper Moon?"

The demon grinned, its teeth like shattered glass. "The Upper Moon invited us for a feast. We get to kill you little Demon Slayers as appetizers."

Zenitsu screamed. "I knew it! I knew this mission was cursed!"

Saitama tilted his head. "This is Lower Moon Two? That's not very impressive."

The demon hissed, vines lashing toward Saitama. "Die, bald human!"

The vines wrapped around his torso, tightening like steel cables. Tanjiro drew his sword, about to assist —

— when Saitama flexed slightly, and the vines disintegrated into dust.

"Uh…" The demon froze.

Saitama stepped forward, casually punching the demon in the stomach. The entire upper half of the demon vanished, leaving only trembling legs.

The lower half collapsed, and the demon's head regenerated from the stump, its face twisted in disbelief. "W-WHAT KIND OF SLAYER ARE YOU?!"

"I'm not a slayer," Saitama corrected. "I'm just a hero for fun."

Inosuke was already cheering. "BALDY JUST KILLED A MOON LIKE IT WAS NOTHING!"

But before they could celebrate, the air grew thick — an oppressive pressure weighing down on everyone's chest. From the shadows stepped a taller figure, his pale skin almost luminescent under the moonlight. His six arms were covered in intricate kanji tattoos, each glowing faintly.

"Upper Moon Four," Tanjiro whispered, his grip tightening on his sword.

This demon was nothing like the first. His presence alone made even the insects go silent.

"So you're the bald man who's been causing trouble," Upper Moon Four spoke, voice smooth but venomous. "Muzan-sama told me about you."

Saitama stared blankly. "Huh? Who's Muzan?"

The demon's face twitched. "The King of Demons, fool! You dare not know his name?!"

"Never heard of him."

The demon was visibly trembling with rage, veins bulging on his forehead. "I will erase you and all your pathetic little slayer friends!"

The Upper Moon lunged forward, his six hands weaving intricate symbols in the air, unleashing a storm of black petals shaped like blades, spinning faster than the eye could follow.

Tanjiro shouted, "Water Breathing, Fifth Form—"

But Saitama simply exhaled and waved his hand lazily — and the entire storm of petals scattered, blown away like dust.

The Upper Moon froze. "What…"

Saitama punched him square in the face. The demon exploded into mist, body parts flying in every direction.

For a full minute, no one spoke.

"Was… was that it?" Saitama asked, glancing at Tanjiro.

"I… I think so?" Tanjiro's voice was weak, eyes wide in shock.

Zenitsu fainted. Inosuke just pointed at Saitama, screaming, "BALDY IS A GOD!"

But before anyone could relax, the mist began to reform, the Upper Moon's head regenerating first — his expression filled with terror instead of arrogance.

"What kind of monster are you?!" the demon shrieked.

Saitama frowned. "Wait, you can heal? That's annoying."

The demon turned to flee, realizing Saitama was something no demon had prepared for. But before he could escape—

Serious Sideways Punch.

A punch so fast that it didn't even look like Saitama moved — and the entire forest behind the demon vanished, leaving only a massive trench cutting through the earth. The demon's body vaporized instantly.

Tanjiro, Inosuke, and the freshly-revived Zenitsu could only stare in awe and fear.

"Saitama-san…" Tanjiro swallowed hard. "Are you really human?"

"Yeah." Saitama looked genuinely confused. "Why? You guys are kinda weak if this is all it takes to be a 'strong demon.'"

And with that, Saitama walked off toward the nearest village, looking for something more challenging — or at least a good place to buy snacks.

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End of Chapter 11