Chapter 18: The Gathering of Shadows
The battlefield had fallen silent, but far from the reach of human eyes, something stirred in the depths of the demon realm.
A hidden chamber, carved from obsidian and bones, lay buried beneath layers of cursed energy so thick that even Muzan had once feared to step inside.
At the center of the chamber, a massive crimson mirror flickered to life, its surface rippling like blood under moonlight. One by one, figures appeared within it—silhouettes of demons whose power rivaled legends.
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The Council of the Abyss
Seven thrones stood in a perfect circle, each carved from a different substance—one from molten rock, another from petrified flesh, one from crystalized fear itself. These were the Abyssal Council, demons so ancient that Muzan was a mere child compared to them.
A voice, soft yet suffocating, filled the chamber.
"So… Upper Moon Zero has fallen."
The speaker was Seiryuu, the Abyssal Dragon, whose serpentine body coiled around his throne, made entirely of forgotten souls, their faces twisted in endless agony.
"By the hands of… a human?" another voice sneered, this one belonging to Naraka, the Flame of Eternal Suffering, her body engulfed in black fire that consumed the floor beneath her.
"Not just any human," spoke the tallest of them all, Shinkoku, the Titan of Cursed Blood, his voice like distant thunder. "This one is… beyond understanding."
They had all seen the battle through the mirror. They had all seen Saitama—his effortless strength, his bored expression, his complete disregard for the laws of both demon and human existence.
"He is not part of the natural order," Seiryuu hissed. "A creature like him has no place in this world."
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A New Threat Rises
At the farthest edge of the chamber, a sealed door pulsed faintly, as though something was trying to wake up inside.
A being even the Abyssal Council feared—a demon so ancient it had been erased from history itself.
"He is waking," Naraka whispered, her flames flickering nervously. "If Upper Moon Zero has fallen, the Eclipse Demon will awaken soon."
The room fell into tense silence. Even the Abyssal Council knew better than to speak that name too loudly.
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Back at the Butterfly Mansion
Saitama was sitting cross-legged, happily eating a second bowl of rice.
"Man, the food here is pretty good."
Tanjiro sat across from him, still processing everything that had happened. "Saitama-san… are you really human?"
"Yup. Just trained a lot."
"...What kind of training?"
"Oh, you know," Saitama said, counting on his fingers. "100 push-ups, 100 sit-ups, 100 squats, 10 kilometers run every day. For three years."
The room went dead silent.
"That's it?" Inosuke shouted, standing up. "That's just regular training! I've done more than that!"
"Yeah, but did you ever lose all your hair from it?" Saitama pointed at his shiny head.
"...No." Inosuke sat back down.
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Shinobu's Investigation
Meanwhile, Shinobu was writing furiously in her notebook, trying to understand how a human could punch away cursed energy like it was dust.
"There's no biological explanation," she muttered. "It's like his body rejects logic itself."
"I get that a lot," Saitama said, peeking over her shoulder.
"Gah! When did you—"
"Don't think too hard about it," Saitama said with a shrug. "I'm just here to fight some monsters and eat good food."
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A New Mission
Suddenly, a crow flew through the open window, landing on Tanjiro's shoulder.
"Urgent message! Urgent message!" the crow cawed. "Strange demon sightings near the Ruins of Moonlit Valley! All available slayers are to mobilize immediately!"
"Another mission already?" Zenitsu groaned. "Can't we rest for at least one night?"
"I'll come too," Saitama said, finishing his rice. "Maybe I'll find a good hotpot place on the way."
"Hotpot… place?" Tanjiro blinked. "It's a cursed valley filled with ancient demons."
"Yeah, but there's gotta be food somewhere, right?" Saitama grinned.
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Shadows Watching
As the Demon Slayers prepared to leave, deep in the Ruins of Moonlit Valley, several shadowy figures were already watching.
Demons unlike anything Tanjiro and his friends had ever seen—twisted, otherworldly creatures, half-ghost, half-monster, infused with cursed blood directly from the Abyssal Council.
"Let the humans come," one of the figures whispered, voice filled with twisted glee. "We've been waiting for this feast."
But none of them noticed the real danger.
Far above them, sitting calmly on a broken shrine roof, was Saitama—already there, having accidentally run too fast while looking for hotpot.
"Huh. No hotpot… just creepy monsters."
He cracked his knuckles.
"Oh well. Guess I'll settle for a workout."
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End of Chapter 18