"Bang!"
A deafening crash tore through the night, snapping Kyojuro Rengoku from his thoughts. He turned sharply toward the train window.
The entire Mugen Train shuddered.
The tremor traveled through cold steel and into the hearts of everyone aboard.
Outside, the world looked as though it had cracked open.
Dust and shattered stone erupted skyward, blasted into the air by an overwhelming force. A massive circular shockwave spread outward from the impact point. At its center, the earth had been crushed into a deep crater, soil and jagged rock still suspended midair. Under the dim glow spilling from the train, the swirling debris cast long, shifting shadows that stirred instinctive dread.
As the rumbling faded, the dust began to settle like a thin veil. The moment stretched, unnaturally slow, every sound amplified in the silence.
Within the drifting haze, a dark silhouette took shape.
The air around him seemed distorted, as though space itself bent subtly in his presence. Half crouched at the center of the crater, he resembled a god of calamity emerging from the abyss.
His stillness was more terrifying than motion. Silence often precedes devastation.
When the dust finally cleared, Akaza's patterned face was revealed.
His expression held no emotion. His cold gaze was like winter wind cutting across bare skin, sharp and merciless. Not a trace of damage marked him. His clothing stirred lightly in the breeze as the dust slid from his shoulders without leaving a stain.
The ruined landscape surrounding him only emphasized his composure.
Akaza lifted his head.
His eyes locked onto Raiden and the others through the broken window.
The pressure was immediate, almost tangible. It felt like being marked by a predator with nowhere to escape.
The air grew heavy. Even time seemed reluctant to move.
Raiden exhaled slowly.
He knew Akaza was powerful. He had expected that. What he had not expected was the sheer weight carried in a single glance.
Could he truly protect Rengoku?
The doubt surfaced for an instant.
Then he crushed it.
He would protect the Flame Hashira tonight.
"Upper Moon… Three."
Tanjiro's voice came out hoarse as he read the kanji in Akaza's eyes.
He did not need his sense of smell to understand the difference. This presence alone made his blood run cold.
The demons they had faced before, the Drum Demon, the spider demon Rui, they felt insignificant now.
Akaza merely stood there, and breathing became difficult.
"We will fight outside. We cannot endanger the passengers."
Rengoku's voice was steady. With a single powerful leap, he vaulted through the broken window and landed on the ground below.
Tanjiro and Zenitsu moved to follow.
"Do not move."
Raiden's voice cut through them, sharp and serious.
The three froze.
It was the first time they had heard him speak without that easy smile. The lightness was gone.
"Protect the passengers," he said.
Inosuke, unusually, did not argue. Even he sensed the difference in scale.
"Raiden…" Zenitsu's voice trembled.
Ever since Akaza appeared, Zenitsu's hearing had been overwhelmed, as if countless chaotic signals were crashing inside his skull.
Could Raiden and Rengoku truly withstand this?
Raiden rolled his neck once and gave Zenitsu a faint, confident smirk.
"I will be back soon."
With one hand on the window frame, he leapt down.
Akaza rose fully from the crater, movements controlled and deliberate. His gaze shifted from Rengoku to Raiden.
There was no excitement in his eyes, only calm assessment.
A soft impact sounded beneath his feet.
Then he vanished.
The ground exploded where he had stood, and in the next instant he was already in front of the train, fist driving forward toward Tanjiro and the others who remained inside.
The speed was overwhelming.
Tanjiro's mind screamed at him to move.
His body refused.
The incoming fist carried a violent wind that pressed against their faces.
Just as impact seemed inevitable—
"Thunder Breathing, Second Form: Rice Spirit!"
"Flame Breathing, First Form: Unknowing Fire!"
Lightning and flame erupted simultaneously.
Blinding arcs of electricity intertwined with blazing fire, crashing into Akaza's strike. The force tore through his arm, searing flesh apart in a burst of sparks and heat.
Akaza retreated in a single motion, landing lightly several meters away.
His severed hand regenerated instantly, new flesh forming before a single drop of blood could fall.
"Excellent Nichirin blades," he said calmly, licking the blood from his wrist.
His gaze lingered on Rengoku with clear appreciation.
Then it shifted to Raiden.
"You are weaker," Akaza observed, voice devoid of mockery, "but there is something in you that resembles Lord Muzan. Interesting."
Raiden held his Nichirin blade loosely at his side.
So the aura had not suppressed Akaza in any meaningful way.
Was it because he was an Upper Moon? Because of the greater concentration of Muzan's blood within him?
Akaza tilted his head slightly.
"Why defend the weak?" he asked. "I do not understand."
Rengoku gripped his blade firmly with both hands.
"I will never allow harm to come to those under my protection."
Akaza's expression did not change.
"They would have interfered with our conversation. The one beside you barely qualifies to stand before me."
There was no arrogance in his tone. It sounded like a simple statement of fact.
Raiden almost admired that.
Rengoku's eyes burned brighter.
"I have nothing to discuss with you. Though this is our first meeting, I already find you detestable."
Raiden listened quietly as they spoke.
He did not interrupt.
In fact, he welcomed it.
Every second spent talking brought dawn closer.
And dawn was their greatest ally.