The battlefield was littered with the remnants of the intense fight, and the air hung thick with tension. Despite Tanjiro and Nezuko's victory over one of the Upper Moons, the looming presence of Nakime and the larger demon still made it clear that the battle was far from over. The eerie echo of Nakime's laughter still rang in their ears, and every demon slayer present could feel the weight of what was yet to come.
Rengoku, his fiery aura undiminished, stood tall, his eyes focused on Nakime as she melted in and out of the shadows. "The demons are relentless," he said quietly, his usual warmth giving way to a harder edge. "But they will fall."
Gon, still recovering from his powerful strike, gritted his teeth as he watched the larger demon rise once again. His body ached, and his fists trembled from the raw force he had put into his last attack, but he refused to give up.
Killua, standing beside Gon, was in no better shape. His arm stung from the demon's earlier counterattack, but his eyes were sharp, his mind racing. "We need a strategy," Killua muttered, his silver eyes flicking between the remaining demons. "We can't keep hitting them blindly—they're just regenerating faster than we can do damage."
Before anyone could respond, the larger demon let out a low, guttural growl, his body already healing from the damage Gon and Killua had inflicted. "You're strong," the demon snarled, his smile revealing sharp, blood-stained teeth. "But I'm not done with you yet."
He charged forward, his speed belying his size as he lunged at Gon and Killua, his claws raised to strike.
Gon barely had time to dodge, his body moving on pure instinct as the demon's claws slashed through the air. Killua activated Godspeed, zipping out of range just in time. But the demon was relentless, his attacks coming faster and more ferocious than before.
"He's faster than before!" Gon shouted, his eyes wide as he narrowly avoided another attack.
Killua gritted his teeth, electricity crackling around his body. "He's getting stronger the longer this fight drags on."
Rengoku, seeing the danger, leapt into the fray, his sword blazing with fiery power. "Flame Breathing, Ninth Form: Rengoku!" His sword slashed through the air, a wave of fire following in its wake as he aimed for the demon's exposed back.
The demon roared in pain as Rengoku's attack connected, flames licking at his body, but even as his flesh burned, he twisted around, his eyes filled with fury. "You'll have to do better than that, Hashira!"
Rengoku's eyes narrowed as he prepared for the demon's counterattack, but before the demon could move, a new presence made itself known.
From the shadows, a figure emerged—tall, imposing, and radiating a terrifying power. His skin was pale, almost translucent, and his eyes glowed with an eerie light. The moment he stepped forward, the battlefield seemed to freeze.
Tanjiro's heart skipped a beat. He knew immediately who this was, and the realization filled him with a deep sense of dread. "No…" Tanjiro whispered, his voice trembling. "It's him. Muzan."
The Demon King himself had arrived.
Muzan Kibutsuji, the source of all demons, stood before them, his expression calm but filled with malice. His mere presence was suffocating, the air around him growing heavier with each passing second. The Upper Moons, sensing their master's arrival, seemed to draw strength from him, their auras flaring with renewed intensity.
"Muzan…" Rengoku's voice was low, filled with a quiet fury. He had fought countless demons, but standing in front of Muzan was unlike anything he had experienced before.
Gon's fists clenched, his body trembling not from fear, but from the sheer pressure of Muzan's presence. This was the source of all their suffering, the monster responsible for everything. And now, he stood before them.
Muzan's eyes scanned the battlefield, his expression unreadable as he regarded the demon slayers. "You've come far," he said, his voice smooth and cold. "But this is where your journey ends."
An Unlikely Ally
As Muzan's chilling words hung in the air, the ground trembled once more. But this time, the tremor was not caused by Muzan or his demons. From the darkness behind them, a new figure emerged, their aura distinctly different from the others. Unlike the oppressive power of Muzan, this presence was more chaotic, raw, and untamed.
The figure was a man, tall and muscular, with wild, untamed hair that fell around his face like a mane. His eyes were sharp and filled with a fierce, almost animalistic energy. He wore a long, tattered cloak, and strapped across his back was a massive sword, its blade dark and jagged as if it had seen countless battles.
"Who… who is that?" Gon asked, his eyes wide as he watched the newcomer approach.
Tanjiro's senses flared as he tried to get a read on the man. There was something strange about him—something powerful, but not demonic. "He's not a demon… but he's not human either."
The man's gaze swept across the battlefield, taking in the sight of Muzan and the demon slayers locked in combat. His lips curled into a feral grin as he stepped forward, his voice low and filled with an unsettling intensity.
"You're all making quite the mess here," he said, his tone almost playful. "But it looks like you could use a hand."
Rengoku's eyes narrowed as he studied the man. "Who are you?"
The stranger's grin widened. "Name's Aru. And let's just say I've got a bone to pick with Muzan."
Muzan's cold gaze shifted to Aru, his eyes narrowing slightly as if sizing him up. "You dare to challenge me?" Muzan's voice was filled with disdain. "Who do you think you are?"
Aru chuckled darkly, his grip tightening on the hilt of his massive sword. "Let's just say I'm someone you really don't want to piss off."
Without warning, Aru charged forward, his massive sword raised high as he swung it toward Muzan with brutal force. Muzan's eyes gleamed with amusement as he effortlessly dodged the attack, his movements smooth and almost graceful.
"You're fast," Muzan remarked, his voice filled with dark amusement. "But speed won't save you."
Aru grinned, his eyes gleaming with excitement. "Who said anything about speed?"
Before Muzan could react, Aru slammed his foot into the ground, sending a shockwave through the earth that knocked Muzan off balance. In that split second, Aru's sword came down again, aiming directly for Muzan's neck.
But Muzan, always composed, twisted his body at the last moment, avoiding the fatal blow. His eyes narrowed in annoyance, his aura flaring with deadly intent. "You'll regret that."
As Muzan prepared to retaliate, Gon and Killua exchanged a quick glance. Whoever this newcomer was, he was clearly no ordinary fighter—and his presence had given them an opening.
"We need to help him," Gon said, his voice filled with urgency.
Killua nodded, his body crackling with electricity. "Let's go."
Together, they rushed forward, their attacks aimed at Muzan with renewed determination.
The Battle Intensifies
With Aru now in the fight, the battlefield had shifted. The combined efforts of the demon slayers and this mysterious new ally seemed to disrupt Muzan's usual dominance, forcing him to take them more seriously. His cold, calculating demeanor gave way to a more focused intensity as he deflected their attacks with ease.
Rengoku's flames burned hotter than ever, his Flame Breathing techniques lighting up the night as he fought alongside Aru. Tanjiro, Nezuko, Gon, and Killua worked in tandem, their movements synchronized as they attacked Muzan from all sides.
But despite their combined efforts, Muzan's power was overwhelming.
With a flick of his wrist, Muzan sent a wave of blood-red energy crashing toward them. Gon barely had time to dodge as the energy slammed into the ground, leaving a deep crater in its wake.
"We can't let up!" Tanjiro shouted, his eyes burning with resolve. "If we stop, he'll overpower us!"
Killua's silver eyes gleamed as he activated Godspeed, zipping around Muzan with blinding speed. He struck with lightning-fast precision, his claws aiming for Muzan's vital points.
But Muzan was faster. He caught Killua's wrist mid-strike, his grip like iron as he twisted, forcing Killua to the ground with a painful thud.
"Foolish boy," Muzan hissed, his voice filled with malice. "You cannot defeat me."
Before Muzan could strike the finishing blow, Gon charged forward, his fists glowing with nen as he unleashed a powerful punch. "Jajanken: Rock!"
Muzan released Killua just in time to dodge Gon's attack, his eyes flashing with irritation. "You're persistent, I'll give you that."
But before Muzan could retaliate, Aru was back in the fight, his massive sword swinging toward Muzan with brutal force. "Not so fast, Muzan!"
The Demon King twisted his body, avoiding Aru's blade, but the sheer force of the swing sent him staggering back.
"You'll pay for your arrogance," Muzan growled, his aura darkening as he prepared to unleash his full power.
The battle was far from over, and the stakes had never been higher.