One Piece: With Sign-in System

Ron slowly lowered his fist.

Tanjiro, who had just witnessed that strike, stood frozen in shock, his heart pounding wildly.

"R-Ron… sir…?"

Ron looked down at him and smiled.

"No need to look so surprised. Didn't I tell you already? I'm invincible."

Far ahead, Akaza—his body half-destroyed, having been blown back dozens of meters—stared at the black-clad young man in absolute disbelief.

A… a human?!

Impossible!

That raw, devastating power—how could it possibly come from a mere human?!

Akaza couldn't accept it.

Ron gave him a passing glance.

And in that moment—

"!!"

Akaza's expression twisted violently.

As a warrior honed through countless life-or-death battles, his instincts screamed louder than ever before. In that instant, an overwhelming pressure swept toward him like a tidal wave, nearly suffocating him.

His battle-hardened body—stronger than steel and impervious to most attacks—felt as if it were about to be crushed without mercy.

It was just… his aura.

Yet it struck more fear into Akaza than anything he had ever felt before.

Even more than the oppressive dread that Muzan Kibutsuji exuded.

Akaza, the warrior demon who had dedicated his entire existence to fighting, found himself… unable to summon even a shred of will to fight.

His instincts recoiled. His body trembled.

For the first time in centuries—

He was afraid.

He lost composure entirely, his voice tinged with a panic he couldn't mask.

"No… No way! There can't be anyone in this world stronger than Lord Muzan!"

Though his body was rapidly regenerating, fear clouded his gaze as he stumbled back, staring at Ron.

"Just what the hell are you?!"

Tanjiro and Inosuke stood dumbfounded behind him.

Akaza—the Upper Rank Three of the Twelve Kizuki. To them, he was already a being so strong he might as well be from another dimension.

There was no opening, no weakness—they couldn't even follow his movements with their eyes. Facing him meant certain death.

But now…

That overwhelmingly powerful demon was…

…afraid?

"I'm human, of course."

Akaza's eyes flew open at Ron's calm reply.

"No. That's impossible! There's no way a weak, disease-ridden, aging, desire-driven human could possess such power!!"

"…You're the one to be pitied."

Ron, hands clasped behind his back, stood motionless, his azure eyes calm and unwavering as they fixed upon Akaza in the distance.

"To throw away your humanity just to gain this level of strength… Is that all you've amounted to?"

Akaza's pupils shrank sharply.

"I'm starting to get bored. Guess it's just your unlucky day, running into me."

Ron's voice was flat, almost casual, as he raised his right hand—palm facing up—and gestured toward Akaza.

"But since you call yourself a warrior, I'll let you strike first."

"Don't even think about running. You won't escape."

Akaza stared into those cold, clear blue eyes and felt as if he had been dropped into an icy abyss. His entire body trembled uncontrollably.

His instincts screamed.

If he turned to run, he would die.

Clenching his fists tightly, Akaza drew upon every ounce of focus he had and slipped into a battle stance.

Destructive Death: Compass Needle!

Technique deployment!

A flurry of snowflake-like patterns swirled out beneath his feet, and a massive surge of combat energy erupted from within him.

Even from a distance, Tanjiro and Inosuke could feel the suffocating pressure creeping toward them like an invisible blade.

But Akaza… still didn't move.

He stared intently at Ron, who stood lazily across from him, his posture relaxed, brimming with openings.

Too many openings.

And yet—

This bone-chilling sense of impending doom…

As if the moment he dared make a move, his head would be rolling on the ground.

"Still not making a move? I was hoping to grab some sakura mochi on the way back. I really don't want to waste time on you. Maybe I should just strike first."

Ron casually scratched his chin, then slowly moved his hand to rest on the hilt of the old blade at his waist.

Akaza's pupils shrank sharply.

With a loud boom, he stomped down with all his might, the ground trembling beneath his feet—and in the blink of an eye, his form vanished from sight.

A fraction of a second later—

A devastating, annihilation-charged punch hurtled toward Ron's face.

Destructive Death: Final Form – Annihilation Type!

"Ron, look out!!"

Tanjiro couldn't stop himself from crying out, overwhelmed by the sheer pressure of the incoming attack.

But Ron simply smirked.

He leaned slightly forward—and with a casual motion, thrust his right fist forward. A swirling, white vapor coiled around his knuckles.

And then—impact.

The moment their fists collided—

Akaza's powerful punch, the culmination of countless battles and centuries of refinement, disintegrated like a soap bubble crushed by a hammer. Crumbled. Shattered. Destroyed.

And next—

His entire body began to crumble from the point of impact. Inch by inch, it disintegrated at an unnatural speed.

Within a second, only his head remained.

Plop—it hit the grass with a dull thud.

Akaza, reduced to nothing but a lone head on the ground, stared up blankly.

That… was it?

Just one punch?

Was this the so-called power he had sacrificed everything for? The strength he had abandoned his humanity to obtain? The reason he devoured human flesh, fought endlessly, seeking eternity?

And it ended like this?

"I win," Ron said with a faint smile, his brilliant blue eyes gazing down at the severed head like he was merely inspecting a kicked-over ball. "Seems even demons have their limits."

Then, without a change in expression, Ron raised his right foot and crushed Akaza's head beneath his boot.

In the final flicker of consciousness before everything went dark, Akaza's face twisted into a bitter, self-deprecating smile.

So this was his life…

A pitiful, laughable existence.

Ron turned, facing the still-frozen Tanjiro and Inosuke.

"Alright," he said with a light tone, "let's go."

"Time to buy some sakura mochi."

…

"Akaza… is dead?!"

In a quiet study inside a human household, Muzan Kibutsuji—currently disguised in the form of a young child—abruptly lost all trace of innocence. His childish face contorted into something monstrous, veins bulging at his temples, crimson eyes brimming with bloodshot fury. The vertical slits of his pupils gleamed with a malevolent light.

"What the hell happened?! Who killed him?!"

He pressed a hand against one of his eyes, attempting to peer through the blood he had left in Akaza's body to witness the final moments.

But the distance was too far—he couldn't see anything clearly.

"Was it those Demon Slayer swordsmen who defeated Enmu?"

"They took down Akaza too…? I seriously underestimated those insects."

He slowly lowered his hand, rage burning behind his glowing red pupils. Veins bulged more violently around his eyes as murderous intent surged from his entire body like a tidal wave.

"The Demon Slayer Corps… how utterly vexing."