The World On His Shoulders | Demon slayer x Male reader

Chapter C

Play the saddest, climax like, and depressing emotional music you can find, or epic and intense or whatever.

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❛ ━━･❪ ❁ ❫ ･━━ ❜

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Muzan knew he had to end this fast. Ten minutes was all he had before the sun would turn him to ash, and if he couldn't defeat Y/N now, he'd be trapped. His eyes narrowed between anger and fear.

He unleashed his most brutal attack yet, his body shifting into a mass of writhing tentacles and appendages. Each movement carried the strength to pulverize rock, enough to tear through walls with ease. The tendrils were aimed at Y/N from all sides, whipping through the air with ear-piercing force. He aimed to overwhelm Y/N, hoping to cut him down or force him into submission. It was a hurricane of tentacles, every strike infused with energy.

Y/N stood his ground, lifting his sword calmly. His blade glowed with a distinct light, the water forming around it in a spiraling motion. As he dragged the edge against his palm, his blood mixed with the water, amplifying its flow. The water came from the sword, forming a cascading stream that enveloped the blade in a turbulent current.

The first tentacle struck, but the water absorbed the impact, moving around the appendage and dispersing its force. The water from Y/N's sword cut through another tentacle with clean precision, the severed piece hitting the ground. Each time Muzan attacked, the water responded with graceful yet powerful movements, turning his violent strikes into harmless splashes.

One of Muzan's strikes got through slashing across Y/N's torso. The cut went deep, tearing into his flesh. It sliced through muscle, exposing raw tissue and bone. The wound stretched from his right shoulder to his left hip, a gruesome gash that would've incapacitated anyone else.

Y/N staggered, but he didn't go down. The gash across his body began to close, muscle knitting together, tissue reforming, and skin sealing itself. The regeneration was fast, almost as if his body refused to stay wounded for long. Within moments, the gruesome cut had faded, leaving only faint traces of blood on his skin.

Muzan knew he had to find a way to absorb Y/N and escape, or it would be the end for him.

Y/N reflected on his memories and dreams, knowing that he now had mastered the Breathing Style from Yoriichi himself. It wasn't just about wielding the blade or understanding the technique—it was about discovering the precise wrist angles, footwork, and breathing rhythms that brought the dance to life. He'd always struggled with the twelve forms due to his frail health. But now with his renewed strength, he felt the flow of Sun Breathing coursing through him, an ancient power passed down by the greatest swordsman in history.

He accessed the "Transparent World," time and motion slowed, granting him insight into the battle's details. This was a gift from Yoriich. Y/N felt gratitude for the guidance, and the chance to learn the twelve forms and understand how they connected. These forms were designed to last until dawn, to stall Muzan long enough for the sun to rise and vanquish him. Yet, a lingering doubt remained in his mind. Even Yoriichi the greatest of all time, couldn't finish the job.

Y/N sighed, not from exhaustion but from the weight of a life spent watching loved ones die and suffer. The endless loss, the grief—it was all too familiar. What he yearned for was a future with his remaining friends, his wife, and his baby girl.

 But deep down, he knew that the odds of killing Muzan were slim, that he might need to sacrifice himself to ensure this thing would never harm anyone again.

It didn't matter. If it meant taking down Muzan, he'd do whatever it took, even if it meant facing the sun himself.

Muzan's attacked with a shockwave that tore through the air. Y/N replied with a deadly calm, "Serpent Breathing." Nearby Obanai gasped his right hand gone, clutching the stump where his hand once was.