The following days at the Demon Slayer Corps headquarters were grueling. From the moment the sun rose until long after it set, the air around the training grounds was filled with the sound of swords clashing, feet pounding the earth, and heavy breathing. Every member of the Corps seemed to sense the urgency in the air—something dark was on the horizon, and everyone knew they had to be ready.
For Gon, Killua, and Tanjiro, the pressure was especially intense. The knowledge that Muzan was on the move weighed heavily on them, and every moment of training felt like a step closer to the inevitable battle with the Demon King.
Today was no different.
Gon stood at the edge of the training grounds, his fists clenched as he stared down a large wooden dummy placed in front of him. He could feel the familiar energy of his nen coursing through his body, crackling like electricity beneath his skin. His mind was focused, every muscle in his body coiled and ready to explode into action.
Behind him, Killua and Tanjiro watched in silence. Both of them were feeling the weight of the intense training that had pushed their bodies to the limit.
"You ready, Gon?" Killua asked, his arms crossed. His silver eyes gleamed with a mixture of curiosity and challenge.
Gon nodded, a determined smile spreading across his face. "Yeah. I've been working on something new."
With a deep breath, Gon centered himself, letting the energy of his nen flow into his hands. His fists began to glow with a faint blue light, the air around him shimmering with power. He gritted his teeth, his eyes locking onto the dummy in front of him.
"Jajanken: Rock!" Gon shouted, his voice echoing across the training grounds.
He shot forward, his fist slamming into the dummy with immense force. The ground beneath him cracked, and the dummy shattered into pieces, debris flying in every direction.
Killua raised an eyebrow, clearly impressed. "Not bad."
Tanjiro, standing beside Killua, smiled. "Gon, your control over your nen has improved a lot since we started training."
Gon turned to face them, his eyes shining with excitement. "Thanks! I've been working on focusing my attacks more, just like you said, Tanjiro."
Tanjiro nodded, his expression serious but proud. "That's the key. Power is important, but if you can't control it, it can turn against you."
Gon's face lit up. "I'm learning! But I still want to push it further. I want to make sure I'm ready for the next time we face Nakime—or any of the other demons."
Killua smirked, his usual cool confidence returning. "Same here. That demon moved like a ghost. If we don't step up our game, the next fight could be our last."
As the trio discussed their progress, the familiar sound of Rengoku's booming voice filled the air, drawing their attention. "Gon! Killua! Tanjiro! Come here!"
The three turned to see the Flame Hashira standing at the center of the training grounds, his arms crossed and his usual fiery enthusiasm burning brightly in his eyes. Beside him stood Tengen Uzui and Shinobu Kocho, their expressions serious but filled with the same determined energy.
"Your training is going well," Rengoku said as they approached. "But there's still much to learn. Today, we're going to push you even harder."
Tengen grinned, his eyes gleaming with excitement. "We've seen what you can do, but now it's time to see if you can keep up with the best of us."
Shinobu smiled softly, though her eyes remained sharp. "You've made impressive progress, but don't get too comfortable. The demons you'll face won't hold back, and neither will we."
Killua's smirk widened as he cracked his knuckles. "Sounds good to me."
Gon, his face lit up with excitement, bounced on his feet. "What's next?"
Rengoku's grin widened. "You'll be sparring with the Hashira."
The words hung in the air for a moment, and both Gon and Killua's eyes widened in surprise.
"Wait, you mean…?" Gon started, looking at Rengoku in disbelief.
Rengoku nodded, his fiery aura flaring to life around him. "That's right! You've trained hard, but the only way to truly prepare for what's coming is to fight against those who have faced the Upper Moons themselves. Today, you'll fight us."
Killua's eyes narrowed, his body tensing with anticipation. "All of you?"
Shinobu's smile didn't waver. "Don't worry, we'll go easy on you."
Tengen cracked his neck, his broad grin flashing in the sunlight. "But not too easy."
Tanjiro stood beside his friends, his expression serious. He knew just how powerful the Hashira were. They were on a completely different level than anyone Gon or Killua had faced before. Sparring with them wasn't just a test—it was a way to push them beyond their limits.
"We're ready," Gon said firmly, his fists clenched with determination. "Let's do this."
The Sparring Begins
The training grounds were cleared as the sparring matches began. Rengoku, Tengen, and Shinobu stood at one end, their expressions calm and focused. On the opposite side, Gon, Killua, and Tanjiro prepared themselves for the intense fight ahead.
The air around them crackled with anticipation, and the other demon slayers who had been training nearby gathered to watch. There was a sense of awe and respect in the air—this wasn't just a normal training session. It was a clash between the strongest warriors of the Demon Slayer Corps and two of the most powerful Hunters from another world.
"Don't hold back!" Rengoku shouted, his voice filled with excitement. "We're going to push you as hard as we can!"
Gon and Killua exchanged a glance, their expressions hardening with resolve. They knew what they were up against, but that didn't matter. They were going to give everything they had.
Without warning, the fight began.
Rengoku was the first to move, his body a blur of speed as he closed the distance between them. His Nichirin Blade flashed in the sunlight as he swung it toward Gon with incredible force.
But Gon was ready. His eyes narrowed as he activated his nen, his body moving with practiced precision as he dodged Rengoku's attack. The ground cracked beneath them as Rengoku's blade hit the earth, but Gon had already moved, his fist glowing with nen as he countered with Jajanken: Rock!
Rengoku's eyes gleamed with excitement as he blocked the attack with his sword, the force of Gon's punch reverberating through the air. "Excellent!" he shouted, his voice filled with admiration. "That's the spirit!"
Killua, meanwhile, had already darted toward Tengen, his Godspeed activated at full power. His body moved like lightning, faster than the eye could track, as he closed in on the Sound Hashira. "Let's see if you can keep up!" Killua shouted, his claws crackling with electricity as he aimed for Tengen's side.
But Tengen was no stranger to speed. With a wide grin, he dodged Killua's attack at the last second, his dual Nichirin Blades flashing as he swung them toward Killua with a flourish. "Not bad, kid! But you'll need to be flashier than that if you want to win!"
Killua's eyes gleamed with challenge as he narrowly avoided Tengen's blades, his body twisting with the speed of his Whirlwind technique. "Just wait. I've got more."
Meanwhile, Tanjiro faced off against Shinobu. The Insect Hashira's movements were delicate but precise, her strikes coming faster than Tanjiro had expected. Her blade danced through the air like a butterfly, each movement calculated to find an opening in Tanjiro's defense.
"Your breathing techniques are strong, Tanjiro," Shinobu said softly, her smile never fading. "But you still have much to learn."
Tanjiro's grip tightened on his sword, his breathing steadying as he focused. He had sparred with Shinobu before, but today felt different. He could feel the weight of the coming battle with Muzan pressing down on him, and he knew he couldn't afford to hold back.
With a deep breath, Tanjiro activated his Water Breathing technique, his body moving in perfect harmony with his sword. "Water Breathing, Seventh Form: Drop Ripple Thrust!"
His blade shot forward like a rushing stream, aiming for Shinobu's center. But Shinobu, ever graceful, dodged the attack with ease, her movements light and effortless.
"You're improving," Shinobu said, her eyes sharp. "But you'll need to be faster than that."
The sparring matches continued, each one more intense than the last. Gon's fists clashed with Rengoku's sword, the ground beneath them cracking from the force of their attacks. Killua's lightning-fast movements kept him one step ahead of Tengen's dual blades, but the Sound Hashira's strength and speed were nothing to underestimate.
And Tanjiro, though facing an opponent far more experienced than himself, continued to push forward, his breathing techniques flowing like water as he tried to find an opening in Shinobu's defense.
But no matter how hard they fought, the Hashira were always one step ahead.
Rengoku, grinning from ear to ear, delivered a powerful strike that sent Gon skidding backward, the impact reverberating through the ground. "Incredible! But we're not finished yet!"
Gon, panting but smiling, pushed himself to his feet. "We'll keep going!"
Killua, too, was feeling the strain. Tengen's relentless attacks had kept him on the defensive for most of the fight, but he refused to give in. "I'll show you speed," Killua muttered, his eyes gleaming as he prepared his next move.
As the sun began to set, casting long shadows across the training grounds, the sparring matches finally came to a close. Gon, Killua, and Tanjiro were exhausted, their bodies aching from the intensity of the battle, but their spirits were high.
"You've done well," Rengoku said, his voice filled with pride as he sheathed his sword. "But remember, this was just training. The real fight is still ahead."
Shinobu smiled softly as she wiped a bead of sweat from her forehead. "You've shown great potential. But you'll need to continue pushing yourselves if you want to face the Upper Moons."
Tengen, his usual flamboyance returning, grinned at Killua. "Not bad, kid. You're faster than I thought. But next time, let's make it even flashier."
Gon, panting but grinning, nodded eagerly. "We'll keep training! We'll be ready for anything!"
Killua, though exhausted, smirked. "Just you wait. We're not done yet."
Tanjiro, standing beside his friends, felt a sense of pride welling up inside him. They had come a long way, but he knew they still had much to learn.
And as the night settled over the headquarters, the weight of the coming battle with Muzan hung heavy in the air. But for the first time, there was a sense of hope—a belief that, together, they might just stand a chance.