Chapter 50: Echoes of the Forgotten Sun
The earth's tremble grew stronger, like a heartbeat deep beneath the soil. Dust danced in the air as ancient energy stirred awake. The Hashira, exhausted yet alert, instinctively raised their swords, unsure what they were sensing — but it felt… wrong.
Tanjiro's nose wrinkled as he sniffed the air. "This scent… it's not a demon's. It's… ancient, but familiar."
Saitama scratched his head. "Ancient? Like… an old man?"
"No," Giyuu said softly. "It feels like something older than even Muzan. Something that was supposed to be gone forever."
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The Ground Splits
Suddenly, cracks spiderwebbed across the ground, splitting the battlefield apart. From the depths below, a withered hand reached out — skin charred black, veins glowing faintly like molten gold. Slowly, a figure crawled out.
He was dressed in tattered robes, an ancient Demon Slayer uniform, but warped and twisted. His Nichirin Blade was split in two, one side burning with Sun Breathing and the other side pulsing with corrupt black flames.
His face was a mask of agony and fury, yet his presence radiated power — power that rivaled even the Upper Moons.
"Impossible," Rengoku gasped. "That's… Yoriichi Tsugikuni's brother. The one who walked the path of darkness."
Kokushibo's soul fragment, long thought destroyed, had fused with something even darker from beyond the rift.
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A New Kind of Threat
The figure's eyes glowed crimson-gold, a fusion of Sun Breathing mastery and demon corruption. His voice was a broken whisper, like shattered glass grinding together.
"You broke the seal… and now the cursed lineage awakens."
His gaze swept over the Hashira, but lingered longest on Tanjiro, sensing the bloodline connection.
"You carry Yoriichi's legacy," the figure said softly. "Then you shall be the first to fall."
Saitama stepped forward, yawning. "Okay, okay. Can we not do the whole 'ancient evil threatens the world' speech? Just get to the fight part."
The figure's head snapped toward Saitama, eyes narrowing. "And you… you are no slayer. What are you?"
Saitama's expression stayed blank. "I'm just a guy who fights for fun."
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Sun vs. Sun
Without warning, the corrupted figure exploded forward, moving faster than even Zenitsu could track. His broken Nichirin Blade clashed with Saitama's bare hand, sparks flying as heat and pressure blasted outward.
Even Saitama raised an eyebrow. "Huh. That actually stung a little."
The figure's power was a twisted fusion of Sun Breathing and forbidden demon arts, his movements seamless — like a dance made of flames and shadows.
The Hashira couldn't even intervene; the sheer force of the clash knocked them back, forcing them to shield their eyes.
"Is this… the power of a corrupted Sun Breather?" Mitsuri whispered in awe.
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Saitama's Counter
Saitama sighed, shaking out his hand. "Alright. Time to punch another guy into next week."
He cocked his fist back, but the figure split into afterimages, surrounding Saitama from all sides, each image wielding a different breathing form — Flame, Thunder, Mist, and even Moon.
"Okay, that's kinda cool," Saitama admitted. "But—"
He spun in place, fist extended. A full-circle Serious Punch.
BOOM!
The afterimages shattered like glass, and the real figure skidded back, coughing up dark blood.
But his expression twisted into a smile.
"Good," he whispered. "This world still has fighters worth killing."
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Hashira Join In
Despite their fear, the Hashira surged forward, swords flashing.
"Rengoku, assist with Flame Breathing! Tanjiro, Sun Breathing!" Tengen shouted, directing the flow.
Giyuu activated Dead Calm, slicing through the air like a ghost. Mitsuri's Love Breathing wove around her allies' attacks, adding unpredictable flourishes.
Even Zenitsu, trembling, joined the fray. "Thunder Breathing… First Form!"
Together, they forced the corrupted figure onto the defensive, their combined techniques creating a breathtaking tapestry of light and death.
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A New Breathing Form?
As Tanjiro fought, his sword began to glow brighter, his Sun Breathing merging with something new — a trace of Saitama's sheer force. Unknowingly, Tanjiro began to create a new style:
Limitless Sun Breathing.
Saitama noticed, blinking in surprise. "Huh. Copying my vibe? Not bad, kid."
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Cliffhanger
Just as victory seemed possible, the sky split open once more — but this time, it wasn't Azrathol.
It was Muzan.
Or rather, what was left of him after fusing with something from the other side of the rift.
He no longer looked human, or even like a demon. His body was a living void, constantly shifting between forms — tendrils, faces, flames, and shadows all at once.
"I was content ruling this world," his voice echoed. "But now… I see there are other worlds to conquer."
Saitama cracked his knuckles. "Guess lunch has to wait again."
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End of Chapter 50
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