At this moment, in the battlefield where Akaza and Kairo Retsu were fighting, both were locked in fierce combat amid a vast pool of blood. One side sought to shatter the other's skull in a single blow, while Kairo Retsu used the agility of his Insect Glaive and his high defense to continually engage and entangle Akaza.
Meanwhile…
Joseph Joestar, Kazuma, and several members of the Demon Slayer Corps were enveloped in a dense, blood-colored mist. At its center was Tamayo, who was releasing her Blood Demon Art.
The scent from her Blood Demon Art bypassed the brain's natural protective mechanisms, forcibly drawing out the body's full strength. However, the price was—
Intense pain flooding every part of their bodies.
"GAAH! That hurts like hell!" Kazuma kept rubbing his body, nearly in tears.
"It's just a little… ah! Oww oww oww oww!!" Joseph had tried to tough it out, but he only lasted a few seconds before breaking down.
Though the pain didn't impair Joseph or Kazuma's movements, they couldn't help but respect the Demon Slayer Corps members who bore the same pain without flinching.
"As for storming the battlefield… I'll leave that to you." Shinobu Kocho had initially intended to accompany them, but her physical capabilities truly weren't enough to pose a real threat to an Upper Rank demon with swordplay alone.
"Sensei, I'll do my best," Kanao reassured her.
"The Crimson Blade…"
Tanjiro tightly gripped his Nichirin Blade, trying to activate the "Crimson Blade" state, just as Joseph and Kazuma had informed him—by clenching the sword with all his strength.
The first to achieve this, unexpectedly, was Giyu Tomioka, whose face showed clear confusion as his blade suddenly turned crimson in his hands.
"Ohhh! The blade of that bowl-cut guy turned red!!!" Inosuke shouted with excitement at the sight of Giyu's blade.
"I'm doing it too!!"
Inosuke began striking his two blades together. With his body's output heightened beyond normal by the Blood Demon Art—his muscles tearing and healing rapidly—the blades gradually turned red under the strain of his strikes.
Seeing more and more Crimson Blades manifesting, Joseph made his move: "In that case! Let's go! Remember the plan—"
Right as he spoke, Kazuma placed his hand on Joseph's shoulder, and the two vanished into the shadows simultaneously.
The others, who had been fully prepared, shot forth like arrows from a bow, racing toward Akaza at top speed.
Each fighter pushed themselves to their physical limits—ignoring bodily wear entirely—and with Tamayo's spell unlocking their mental restraints, their speed surpassed anything they'd ever achieved before.
Akaza, in turn, sensed the sudden intrusion of unfamiliar presences into the range of his Compass Needle.
And these presences… surprised him.
Fighting Spirit—dense, immense Fighting Spirit.
He instantly saw several Demon Slayer Corps members within his line of sight:
Tanjiro Kamado, Giyu Tomioka, Inosuke Hashibira, Kanao Tsuyuri…
Though they had only been absent for a short time, the change in their Fighting Spirit was drastic. Just like Kyojuro Rengoku had been on the Mugen Train—
It carried the scent of death-defying resolve, as if their minds had let go of all fear of self-sacrifice. Within this state, their Fighting Spirit surged with terrifying momentum.
The intensity of their auras nearly drowned out Kairo Retsu's comparatively weak Fighting Spirit altogether, causing a twinge of excitement to stir within Akaza.
Yet he also felt a faint sense of unease.
There was something about their crimson-bladed Nichirin Swords… a presence that even he, as an Upper Rank demon, instinctively feared.
Akaza didn't care how this transformation had come about. All he knew was—
In this suffocating pressure, he was inching ever closer to the "Supreme Domain."
"So this was your plan, Kairo Retsu!!" Akaza roared. "I don't know how you pulled this off… but in such a short time, you've actually made their Fighting Spirit surge this much!!"
"In that case, COME!!!"
Akaza stepped forward violently, unleashing his Blood Demon Art with full force, now clearly sensing the swelling auras before him.
"Let me crush every last ounce of this Fighting Spirit! And step into that Supreme Domain!!"
"Shut your mouth, you tattooed bastard!!" Inosuke bellowed, charging in with crossed dual blades, trying to saw through Akaza's body.
But in an instant, Akaza reacted. Not only did he dodge Inosuke's assault, he swung his fist into Inosuke's side.
With just one sweeping punch, blood burst from Inosuke's abdomen, and his body flew sideways. Yet no one could spare time to check on him. Everyone's attention was on one thing—
Akaza, who could perceive Fighting Spirit from every direction.
Inosuke, wounded, quickly regenerated and rejoined the fray. Meanwhile, the Demon Slayer Corps members fought recklessly, ignoring every injury except a fatal head blow.
Then—
The moment a Crimson Blade cut into Akaza's body, he confirmed what he suspected.
His greatest threat… was those red Nichirin Blades.
Even a mere graze caused his regeneration to slow and inflicted a searing, sunburn-like agony.
But the higher the pressure, the greater Akaza's fighting spirit burned.
"I'LL UNLEASH EVERYTHING! AND CRUSH YOU ALL!!!"
Akaza's voice boomed as he launched a furious counterattack.
He could sense every refined movement the Demon Slayer fighters made through their Fighting Spirit—this clarity proved to him:
He was nearing the Supreme Domain.
However—
After knocking back all four Crimson Blade users, Akaza suddenly sensed a weak aura… above his head.
Instinctively looking up—
He saw Kairo Retsu descending on him from above.
"At a time like this?! You insignificant weakling!! STAY OUT OF MY FIGHT!!"
Akaza roared and struck at Kairo.
In his current state, he was certain this blow would completely obliterate Kairo Retsu's skull.
Just as Akaza expected—the sensation of skull being crushed echoed through his arm, and Kairo Retsu's body, along with his Insect Glaive, crashed into Akaza, pinning him to the ground.
A desperate attempt to buy time?
Akaza scoffed at the body of Kairo Retsu, whom he had just slain with a single blow.
Before the next round of attacks from the Demon Slayer Corps arrived, he could easily shake off such a powerless weapon.
All he needed to do was cast the glaive aside…
Just as he thought that—
He caught sight of Kairo Retsu's shattered head. The mouth—what was left of it—still wore a beaming grin.
It was only now that Akaza realized…
Why had he only sensed Kairo Retsu's Fighting Spirit the moment the man appeared above him?
Was it truly because his aura was simply too weak compared to the blazing presences around him?
Why had only Tanjiro and the others returned to battle? Where were the rest?
Why had he come to believe that only the crimson blades posed a threat?
As these thoughts flashed through his mind—
Akaza lost his final chance to escape.
And in that very instant, a voice roared beside his ear.
"ORAORAORAORAAAAAA!!!!!!!!!!"