Seifu's voice grew fervent. "I think you're a terrible villain, standing in the way of justice."
Gusion paused and sneered. "You seem to be mistaken."
"Isn't that the truth? Or have you never read history?" Seifu said, gnawing on another snack, his mouth bloody. Clearly, the cannibalistic instincts of a demon were too strong, even for a resilient explorer. Or maybe he simply saw himself as sacred.
"I never said I was fighting for this country," Gusion said coldly. "I simply can't stand you demons."
He knew the twists and tragedies of five thousand years of history, and the nation's suffering in modern times.
He acknowledged his country's wartime evils and admired the heroes who fought and sacrificed everything, but that didn't mean he'd ever join Muzan's camp.
"But we are heroes! Lord Muzan could become a hero. Once we overcome the sun, we'll rule this land," Seifu said, growing manic. "Isn't there something wrong with you?"
Gusion lowered his stance, his voice grim. "Shut up. Comparing Muzan to those who fought and died for their homeland is the greatest insult."
Lightning crackled around him, white steam and purple mist rose, and Gusion's eyes flashed with fury as he slashed at Seifu.
In a flash, dozens of meters vanished, his black blade slicing toward Seifu's neck.
Seifu's manic smile faded, replaced by a strange grin. Even though his head was severed, he remained alive—he'd cut his own head off to dodge the attack, a trick only demons could do.
Gusion's strike missed. At that moment, a door appeared behind Seifu; inside was a brightly lit, labyrinthine space—the Infinity Castle.
Unable to stop or change direction, Gusion was forced inside by his own momentum.
Seifu caught his own head, reattached it, and leisurely entered after him.
Bang—
As Seifu stepped through, the door slammed shut.
Both entered the Infinity Castle, descending in mid-air. Seifu looked down at Gusion, smiling. "You brute, so easy to provoke. Did you really think I'd fight you alone?"
Gusion stabilized himself on a platform, while Seifu landed on a higher one, looking down. "Before you came, you must have wondered if the Demon Slayer Corps' base was exposed, right?"
Gusion surveyed the surroundings. At the edges of each platform, and in the gaps behind doors, countless demonic eyes stared at him—hundreds, at least.
No wonder demon attacks had decreased recently; Muzan had gathered his forces here.
Besides the weak demons, Gusion sensed several powerful auras closing in, blocking every escape.
Hearing Seifu's words, Gusion frowned. He realized he'd made a mistake.
"The Demon Slayer Corps' previous hiding methods weren't great. After you changed your relocation patterns, we couldn't act during the day, so we only narrowed it down to a general area," Seifu said, "But thanks to you, I now know exactly where your base is."
As he spoke, he started counting on his fingers. "Based on your attack speed and the time it took you to get here, I can figure out how far you came. Considering the message transmission and your response time, I know the distance you traveled."
"You came from the east. Fifty kilometers to the east are only a few old houses, no villages or towns. Easy to find."
Seifu smiled down at Gusion. "So, you exposed the Demon Slayer Corps' base. You're the one who will get the Hashira killed."
Gusion stood calmly, lightning no longer crackling, only a faint purple mist drifting about. "And?"
"Don't you care? Don't you like the Hashira and the Corps? Your recklessness will get them all killed. Shouldn't you be more furious, more desperate?"
Seifu squatted, looking down at Gusion. "But don't worry—you'll die before them."
As Seifu finished, several figures landed on Gusion's platform.
"You seem strong. Why hate demons? Join us, and we can spar every day," said a demon leaping from the west—a man with short pink hair, golden eyes, pale skin covered in blue convict tattoos, blood-red nails, purple-red top, and prayer beads on his ankles.
From his appearance, Gusion instantly recognized him as Upper Moon Three, Akaza.
"Akaza, I like your idea, but he seems to hate us. He won't join, will he?" said another man with white oak hair, rainbow-colored irises, and clown hats over his eyes, dressed in black with a lazy smile—Upper Moon Two, Doma.
"Doma, be serious. The enemy is strong, and Lord Muzan is watching," said a deep, commanding voice from the north.
A man in a purple snake-patterned kimono, black hakama, and long red sideburns tied in a high ponytail landed. He had six red-gold eyes; the left and right center irises were marked "Upper Moon One."
Kokushibo!
Gusion looked at the gathering of Upper Moons and smirked. "Quite the welcome. You really went all out to lure me into the Infinity Castle."
"You've already killed two Upper Moons. Of course, we have to finish you," Seifu said, jumping down to Gusion's level. He couldn't stand higher than Kokushibo, who cared a lot about status.
Seifu had planned this, and Muzan agreed. Muzan had been uneasy since seeing Gusion in Asakusa.
Luring Gusion into the Infinity Castle meant he had no escape—no one could help him. Surrounded by all the Upper Moons, he had no chance.
Gusion took a deep breath, his spirits rising. "I suppose I should thank you."
"Thank me? I won't leave your corpse whole just because you beg," Seifu said, puzzled by Gusion's calmness.
"These two months, I tried everything to enter the Infinity Castle—but you invited me in," Gusion grinned, showing white teeth.
At his words, the Upper Moons all tensed, sensing his surging aura.
Akaza, closest, instinctively jumped back, putting distance between them.
Seifu's triumphant smile froze.
"Looks like we've let a real monster in," Doma said, backing away with a fake smile.
Only Kokushibo remained unmoved, hand on his sword, six eyes locked on Gusion. "A worthy opponent."
Gusion fully unleashed his mastery of Thunder Breathing, combined with his sword's powers, boosting his stats to 36!
He quickly scanned the Upper Moons' attributes:
[Upper Moon Four—Seifu]
Constitution: 34
Strength: 31
Agility: 38
Spirit: 35
Charisma: 19
[Upper Moon Three—Akaza]
Constitution: 38
Strength: 38
Agility: 38
Spirit: 20
Charisma: 13
[Upper Moon Two—Doma]
Constitution: 37
Strength: 35
Agility: 39
Spirit: 40
Charisma: 20
[Upper Moon One—Kokushibo]
Constitution: 42
Strength: 40
Agility: 40
Spirit: 30
Charisma: 1
[]
In terms of stats, Gusion was only clearly superior to Seifu, and still much weaker than Kokushibo. But these demons instinctively became wary—Gusion's combat skill was on another level.
Even Akaza, a martial arts fanatic, was only at a master's level in combat; Kokushibo might be close to Gusion, but not quite equal.
With Gusion's body at this level, as a demon slayer, he could threaten their lives—so the Upper Moons instinctively kept their guard up.
But Gusion's aura still didn't make Kokushibo feel truly threatened, so Kokushibo calmly stepped forward, ready to strike first and end Gusion.
Normally, he'd want to recruit someone this strong, but for some reason, seeing Gusion triggered memories he'd rather forget.
High above, a figure stepped to the edge, looking down on the battlefield.
He wore a sharp suit, a stylish white hat, and cold, blood-red slit pupils—Kibutsuji Muzan.
"At last, you show yourself," Gusion said, lightning crackling around him as he looked up at Muzan.
The demons waited, not attacking, clearly awaiting Muzan's orders.
Gusion locked eyes with Muzan. "You've got guts."
Within the Infinity Castle, some demons and explorers felt anger, and others mocked Gusion—how dare he provoke Muzan at death's door?
Surrounded, with Muzan overseeing, how could he survive?
But as Gusion finished, his aura surged again. Muscles swelled under his clothes, and dark purple demon markings appeared on his skin, forming strange patterns on his face.
Superheated steam burst from Gusion's mouth with a whistle, his stats jumping to 40 in his demon god state!
He crouched, muscles bulging, and in a flash, the platform exploded with thunder, stones flying like a blooming flower.
Lightning shot into the sky, air rippling with a deafening boom—shaking the entire Infinity Castle!
Before Muzan could react, Gusion soared up like a god of thunder, his deadly black blade slashing for Muzan's head!
In that instant, Muzan smelled death—just like centuries ago.