Nakime crawled forward with all her might. As her arm and legs slowly regenerated, the black blade would fall again, severing them once more.
As Nakime struggled, Gusion stabbed his sword into her neck, pinning her to the floor. He crouched down, grabbed Nakime's hair, forcing her to look up. The blade cut a long gash in her neck as he did so.
Gusion stared into Nakime's single eye. "If you keep regenerating, I'll chop your head off. Understand?"
Nakime's eye filled with blood and tears, her mouth opening and closing, but with her throat pierced, she could only make hoarse, agonized noises.
Gusion slammed her head back to the floor, the blade grinding her neck. He yanked her head up again, making her meet his gaze. "I asked if you understand—why aren't you nodding?"
Nakime felt this man was more demonic than any demon—an absolute devil. Shaking with fear, she forced herself to nod, even as pain shot through her scalp and neck.
"I want to get out—take me where Muzan just went. Open the door."
Gusion ordered. He didn't understand the Infinity Castle's structure, but Nakime controlled it. If he killed her outright, he could be trapped. Even if the castle collapsed and spat him out, who knew where he'd end up? Besides, his original location was far from the main battlefield.
Nakime whimpered, tears streaming down her face as she shook her head.
She was one of Muzan's more loyal subordinates. The thought of betraying Muzan made her shiver.
To her, though Gusion was terrifying, Muzan was even more so.
"Looks like I'm still too gentle."
Gusion smiled kindly. "Don't be fooled by my gentle appearance. I actually know quite a few torture techniques."
He'd learned from ancient texts, not always killing his targets immediately, but extracting information when needed.
Martial artists usually held out, but his ancient joint-breaking techniques would always make them talk.
Demons could regenerate, but that didn't mean they didn't fear pain.
"Mm... mm! Mmm!! Mmm...!"
Nakime's whimpers and screams echoed through the dark room. After ten minutes, Gusion looked at Nakime, now drooling, crying, and leaking other fluids, and withdrew his hand.
"So—do you want me to keep massaging, or will you open the door and bet your boss can defeat me?"
His voice was like a demon's whisper, making Nakime shudder.
She looked at the biwa in Gusion's hand, then cautiously glanced up for permission. With his nod, she regenerated a hand and plucked the strings.
Plang—
With a strum, a door opened before Gusion and Nakime, revealing the nine Hashira battling Muzan outside.
Thunderous explosions filled the air as Muzan unleashed his Blood Demon Art. Countless tendrils whipped around, pushing back the nine Hashira and Tanjiro's group.
Muzan was already exhausted. Though Tamayo's medicine hadn't entered his body in large quantities, it was enough to sap his endurance.
Though it was still far from dawn, Muzan was considering retreat. He realized his hunt was doomed to fail, planning to drive the Hashira back and escape to Infinity Castle.
As for Gusion inside the castle, Muzan could have Nakime eject him and then hide for a century until this generation of Hashira died out, then search for Nezuko again.
In Muzan's mind, Nezuko was still a demon immune to sunlight, not knowing she'd become human. He thought waiting a century was fine.
Even if he knew Nezuko was human, he would still choose to flee.
The nine Hashira were terrifying—especially the towering, blind Stone Hashira. Muzan felt only Kokushibo could reliably defeat him one-on-one; the other Upper Moons would likely lose.
Muzan believed he could defeat the Stone Hashira at full strength, but he wasn't at his peak. These devious Hashira even coated their blades in poison, continually weakening him and slowing his recovery.
Every second, much of his power was spent fighting off cellular decay from the poison, while also fending off the Hashira's assault.
The worst part? After all this time, he hadn't killed a single Hashira.
Not to mention, not even the participating kids had died. It was absurd.
Bang—
As the Infinity Castle's door opened, Muzan's first reaction was relief. His loyal Nakime had come to support him without even being told.
But when he glanced back and saw inside the castle, he saw Nakime—tear-streaked, broken—being held by the hair by Gusion, facing Muzan.
Standing there, Gusion flashed a wide, toothy grin, locking eyes with Muzan.
"Ugh... ahh..."
Nakime, with her throat impaled, could only moan desperately at Muzan, trying to say: Run!
Muzan didn't even stop to consider if Nakime had betrayed him. The moment his eyes met Gusion's, his scalp tingled with terror.
He saw no sign of Kokushibo or any other demon. Gusion had forced Nakime to open the door—what did that mean?
It meant the Infinity Castle was wiped out!
How much time had passed? Twenty minutes?
An unnamed fury rose in Muzan's chest. He cursed, "Useless trash, all of them!"
In just twenty minutes, Kokushibo and the other Upper Moons were annihilated. Disgraceful.
He once thought highly of Kokushibo, even treating him with respect and sharing his blood, but when it came down to it, he was useless.
Muzan's rage quickly turned to panic.
For in the instant he met Gusion's eyes, Gusion exploded into motion, bursting from the castle toward him.
Though he scorned his demons, Muzan truly feared Gusion, who had cleared the castle in just twenty minutes. Instinctively, he turned to flee.
No hesitation—he sprinted away, extending countless tendrils to propel himself far from danger.
It wasn't that Muzan didn't want to return to the castle—but as Gusion charged, he beheaded Nakime. With her dead, the Infinity Castle lost its controller and began to collapse. Even as its master, Muzan would need time to reconstruct it.
"Don't let Muzan escape!"
Tanjiro roared, unleashing Hinokami Kagura, waves of flame slashing to cut off Muzan's escape.
With the battle so dire, he'd sent Cammillia to protect Nezuko and joined the fight himself. His teamwork with Zenitsu and Inosuke gave Muzan trouble.
The other nine Hashira also attacked, their breathing techniques unleashing a barrage of sword strikes, blocking every escape route.
Gusion, stepping out of Infinity Castle, scanned the nine Hashira. Though all were injured, none had died—he was satisfied.
He'd arrived just in time. Muzan, cowardly as he was, would have soon realized the Hashira were running out of stamina.
Their breathing techniques were explosive but short-lived. With Gusion's godlike strengthening, their endurance had dropped further.
A few more minutes and the Pillars would have started to fall from exhaustion. With such a long night, Nichirin blades alone couldn't kill Muzan—they just had to hold out for sunrise.
In this sense, Gusion's godlike upgrade wasn't meant for drawn-out battles. The Mark's side effects were worse, but its duration longer—though older users risked death.
If Muzan had kept fighting, he might have won, as long as Gusion hadn't arrived.
But Muzan had been frightened by the Hashira's valor. Now, with Gusion present, Muzan's will to fight was crushed.
"Damn you, Demon Slayers! Why do you block me!? Why won't you just die!?"
Muzan, forced back, shouted in frustration, "Aside from your families, what do the others I've killed matter to you? What's the point of slaying demons!?"
Swinging his tendrils, he raged, "Compared to your human wars, what's a few people I killed? Can't you just treat it as a natural disaster, as mere bad luck!?"
"Ridiculous."
Gusion's cold voice rang out. With one slash, he severed countless tendrils and stepped to the front lines, blocking Muzan's escape with the Stone Hashira.
The Hashira's veins bulged in anger at Muzan's shameless words. The Stone Hashira roared, "It's time to end your thousand years of evil! We will never allow future generations to suffer by your hand!"
"Muzan! I'll cut you down!"
Tanjiro, recalling his family's tragedy, was even more furious. Activating his demon-god state, a mark reappeared on his forehead, his blade wreathed in a giant ring of fire as he slashed at Muzan.
Muzan, seeing the power of Tanjiro's blade, dared not parry—he instinctively dodged, old scars from Yoriichi's blade throbbing with pain.
Though he avoided Tanjiro's slash, he couldn't evade all the Hashira's attacks. With his movement boxed in, he couldn't escape the most deadly blow.
In that moment, Muzan saw nothing—no Hashira, no Hinokami Kagura, no Inosuke's Beast Breathing, no Zenitsu's lightning.
Only one thing filled his vision: a slash that seemed to split heaven and earth, a pitch-black blade wreathed in dark purple mist and golden lightning, descending with overwhelming killing intent.
Boom—
The blade fell, cleaving Muzan, splitting the ground with a jagged, lightning-shaped fissure over ten meters long.
"Ah—!"
Muzan screamed in terror, "Stay away!"
His wail was filled with despair. Gusion's slash had not only cut his body but destroyed several organs and brains.
Thunder raged through his body, obliterating his cells on a microscopic level, erasing him from existence.
Such overwhelming power—he'd only felt it once before, centuries ago, when Yoriichi Tsugikuni had struck him. Those wounds had never fully healed, even after hundreds of years.
Back then, he survived by self-destructing, splitting into countless pieces to escape.
Now, he had to do the same. To Muzan, Gusion was as terrifying as Yoriichi—no, even more so!
Muzan's body began to swell—he was preparing to self-destruct!