Although the Rock Pillar, Gyomei Himejima, could not see the battle, his sharpened hearing from years of training allowed him to grasp what was unfolding.
The Upper Rank demon with the number One engraved in his eyes was already at a disadvantage after their first exchange.
As one of the main forces against Kokushibo, Gyomei understood his strength better than anyone present. That was exactly why he was stunned by Raiden's power.
So this was why the Master had entrusted the aftermath to Raiden.
Gyomei had never doubted the Master's decisions, though he once felt it was inappropriate to leave such responsibility to someone who had only joined the Demon Slayer Corps a few months ago. Now, he understood.
"It's over," Raiden said quietly, exhaling as he looked at the wound on Kokushibo's neck, which healed instantly.
There was fatigue in his voice, but his tone remained steady.
From their brief clash, Raiden had already realized something. Kokushibo no longer exerted the same overwhelming pressure as before. Instead, Raiden had become the one dominating the battle, and that pressure was only increasing.
Kokushibo was still powerful, but Raiden was no longer the same opponent.
This was a fight to the death. Only one would walk away.
Raiden raised his Nichirin blade. Its edge gleamed sharply, releasing a chilling aura.
Suddenly, crimson gold flames surged from the lightning-patterned blade, engulfing it completely. Fire rose along its length, burning fiercely as if it could consume everything in its path.
The air itself seemed to distort from the heat.
Kokushibo felt the danger immediately. Even the Hashira nearby felt their skin sting from the intense heat, as if the entire battlefield had been swallowed by flames.
Raiden lifted his gaze.
The flames reflected in his eyes, turning them the same crimson gold, glowing with a terrifying intensity.
This time, he did not rely on speed.
He simply raised his blade and swung.
The motion looked slow, almost effortless, yet it carried overwhelming force.
A massive wave of flames, threaded with golden lightning, tore through the air and appeared in front of Kokushibo in an instant.
Kokushibo tried to dodge.
But something felt wrong.
No matter how he moved, he could not escape. It was as if the attack had already sealed every possible path.
Realizing this, he steadied himself.
If he could not dodge, then he would face it head-on.
Gripping his flesh-like blade tightly with both hands, Kokushibo spoke in a low voice.
"Moon Breathing, Sixteenth Form, Moonbow, Half Moon."
He slashed upward.
A radiant arc of blade light surged forward, followed by countless crescent-shaped slashes that filled the space ahead. Each one felt solid, like fragments of the moon crashing down.
The air split apart with piercing sounds. Wooden boards shattered, debris scattered, and the battlefield turned chaotic.
The crescent blades, tinged with a faint red glow, shot toward Raiden's attack with lethal precision.
Cold energy spread through the air.
Then they collided.
There was no explosion, only a faint sizzling sound.
Raiden's crimson gold flames swallowed the crescent blades instantly, devouring them piece by piece like a predator consuming prey.
Kokushibo's technique crumbled without resistance.
The flames surged forward, unstoppable.
In the next moment, they passed cleanly through Kokushibo's neck.
His head was severed.
It spun through the air, blood spraying across the floor before it landed and rolled.
Only then did Kokushibo fully register what had happened.
His vision blurred, but he could still see Raiden standing calmly in the distance, his blade lowered as the flames faded.
There was no doubt in his expression.
Kokushibo's eyes filled with shock, then fury.
That same presence.
That same overwhelming dominance.
It reminded him of a battle from a century ago.
His younger brother.
The one chosen by fate.
He had been defeated the same way back then.
And now, once again, history repeated itself.
Why?
He had abandoned his humanity. He had gained power beyond human limits.
So why was he still defeated?
The thought consumed him.
His severed body began to move.
Driven by sheer will, flesh twisted and regenerated at an alarming speed. Bones reformed, muscles grew, and within moments, his upper body began to take shape again.
The Hashira were stunned.
A demon's weakness was its neck. That should have been fatal.
Yet Kokushibo continued to regenerate, faster than even Akaza had.
Tanjiro stepped forward, unable to hide his urgency.
But before he could speak, Raiden raised a hand and gestured for him to stop.
Tanjiro hesitated, then obeyed, trusting him completely.
Raiden walked forward at a steady pace until he stood before Kokushibo's severed head.
He looked down at him.
Kokushibo's body tensed, his regeneration accelerating as desperation took hold. He had no strength to fight back yet, but he pushed himself, hoping to recover enough to strike.
Raiden did nothing.
He simply watched.
Then, without a word, he drove his Nichirin blade into the wooden floor in front of Kokushibo.