Deep within the ever-shifting corridors of the Infinity Castle, silence reigned. A silence so thick it felt unnatural — even the walls, usually pulsating with eerie life, seemed to hold their breath.
At the heart of the castle, Muzan Kibutsuji sat upon his throne of writhing flesh and bones, his pale fingers tapping against the armrest. His crimson eyes narrowed, reflecting flickers of the Upper Moon Six's death — a death so swift, so absurd, that Muzan himself replayed it over and over in his mind.
A single punch.
It wasn't flashy. It wasn't mystical. No Blood Demon Art, no special Breathing Technique. Just a bald man in a cheap cape, obliterating one of Muzan's most feared creations like he was nothing.
The air rippled as the remaining Upper Moons were summoned.
One by one, they appeared, each descending onto the floor with a mixture of curiosity and tension.
Upper Moon Five — Gyokko, his body shifting like liquid art, sneered, "What now? Why are we called? Another useless Lower Moon's death?"
"Silence." Muzan's voice cut through the room like a razor.
Gyokko instantly bowed, body trembling, knowing better than to test his master's mood.
"Upper Moon Six, Kagenami, is dead."
A ripple of shock passed through the room. Upper Moon Four — Hantengu, split into his multiple emotions, each of them reacting differently — fear, anger, confusion.
"Impossible! Kagenami was strong!" Sekido, the wrathful clone, snarled. "What kind of Demon Slayer could—"
"It was not a Slayer." Muzan's voice darkened. "It was a human. A man with no blade, no Breathing, and no mark. He swatted Kagenami aside as if he was a fly."
A strange silence fell over the room.
Douma, Upper Moon Two, chuckled, his fan hiding his grin. "Oh my, how terrifying! A bald man, you say? Maybe he's mastered a secret art of hair removal."
The room remained silent. Even Douma's joke felt hollow in the face of such absurd power.
Kokushibo, Upper Moon One, finally spoke. "A human capable of such strength… is this some ancient technique lost to time?"
"No." Muzan's voice lowered, filled with something none of the Upper Moons had ever heard from him before. "This man is not a Slayer. Not a sorcerer. He's something far worse."
They all felt it — the tiniest hint of fear in Muzan Kibutsuji's voice.
"His power is not born from training or technique. It's not supernatural. It's simply strength in its rawest, most terrifying form. Strength without limit."
Even Kokushibo's usually calm face tensed. "How should we proceed, Master?"
"Investigate." Muzan's eyes gleamed with a cold fury. "Find out everything about this man. His past. His purpose. His weaknesses — if he has any."
"Should we eliminate him immediately?" Akaza, Upper Moon Three, asked, fists clenching in anticipation. "If he is a threat—"
"No." Muzan's fingers curled. "You would be destroyed before you could land a single blow. Even I will not engage him carelessly."
That admission sent chills through the Upper Moons. Muzan, the Demon King, the origin of their strength, feared a human.
"Do not engage him directly," Muzan ordered. "For now, gather intelligence. Use the shadows. Watch him from afar. If he is truly human, he must have limits. He must."
---
Meanwhile, back in the village…
Saitama walked down a dirt road, hands in his pockets, cape fluttering behind him. Next to him, Tanjiro walked in stunned silence, still replaying the battle in his mind.
"I've seen Upper Moons fight," Tanjiro finally spoke. "They're supposed to be terrifying… even the strongest Hashira struggle against them. But you…"
Saitama glanced down at him. "Yeah?"
"You didn't even try."
"Hmm." Saitama scratched his head. "Yeah, I guess I didn't."
Tanjiro almost tripped over his own feet. "Saitama-san… what kind of training did you do? What Breathing Style is it?"
"Oh." Saitama stopped walking. "My training, huh?"
Tanjiro's eyes shone with admiration, ready to memorize every word.
Saitama raised a finger. "100 push-ups."
Another finger. "100 sit-ups."
Another. "100 squats."
Tanjiro blinked. "That's… basic strength training."
"And 10 kilometers of running. Every. Single. Day." Saitama's face was dead serious.
Tanjiro stared at him in disbelief. "That… that's it?"
Saitama nodded. "And no air conditioning in the summer."
Tanjiro tripped for real this time.
"You're kidding, right? That's not a technique, that's just suffering!"
Saitama shrugged. "Worked for me."
Tanjiro was speechless, half admiring and half panicking. "Saitama-san, you're… truly something else."
As they reached the edge of the village, a crow landed on Tanjiro's shoulder.
"Caw! Urgent summons! Slayers to meet at headquarters! Caw!"
Tanjiro's heart skipped a beat. A summons from the Master? That meant something big was happening.
"Looks like we're heading back," Tanjiro said. "Saitama-san, will you come with me?"
"Sure. I've got nothing else to do." Saitama sighed. "Besides, I still haven't found a decent grocery store."
As they walked toward the Slayer headquarters, deep within the trees, a single floating eyeball followed silently — observing every step Saitama took.
Far away, in the Infinity Castle, Muzan leaned forward.
"Let's see what you really are, bald man."
---
End of Chapter 8