Chapter 1: The Rift in Reality

The sun hung low on the horizon, casting a warm golden glow over the forests of the NGL. Gon Freecss, always a lover of nature, paused as they hiked through the dense undergrowth, taking a moment to admire the vivid oranges and reds painted across the sky. Despite the breathtaking view, there was a tension in the air that neither he nor his best friend, Killua Zoldyck, could shake.

"Do you feel that, Killua?" Gon asked, his brow furrowed, his ever-present fishing rod slung across his back.

Killua walked a few paces ahead, his sharp silver eyes narrowing as they darted between the trees. He had felt it too—a strange pulse in the air, unlike anything he'd experienced before. His assassin's instincts, honed from years of training and combat, screamed that something was wrong.

"Yeah, I feel it," Killua replied, his voice low and cautious. "It's nen, but not like anything we've encountered. It's not just powerful—it feels wrong."

The two of them had been sent here on a mission by the Hunters Association to investigate strange nen fluctuations reported in the area. At first, they had assumed it might be the work of a rogue nen user or some creature with a latent ability. But this was different—unnatural, like the energy was bending the very fabric of the world around them.

The forest seemed eerily silent as they walked, the usual sounds of birds and insects conspicuously absent. The further they ventured, the more the atmosphere felt oppressive, the air thick with anticipation. Gon, always perceptive when it came to his surroundings, noticed the way the trees bent unnaturally, almost as though they were recoiling from the energy.

Suddenly, the ground trembled beneath their feet, and a low hum filled the air. Gon instinctively crouched, balancing himself as the earth seemed to ripple like water. The hum grew louder, almost a buzzing now, and just ahead, through a gap in the trees, they saw it.

A faint light shimmered, distorting the air as if the forest itself was bending. It wasn't like any nen aura they had ever seen. The light pulsed, slow at first, then faster, as if it had a heartbeat of its own.

"What is that?" Gon whispered, eyes wide with awe.

Killua stepped forward cautiously, his hands flexing, ready to activate Godspeed if necessary. "Stay back, Gon. We don't know what we're dealing with."

But before Killua could stop him, Gon had already darted forward, curiosity getting the better of him. Typical Gon. Killua sighed, his annoyance tempered by the fact that he knew he'd follow Gon anywhere.

As they approached the source of the light, they found themselves standing before what could only be described as a tear in the fabric of reality itself. The air around the rift felt different, almost like static electricity, raising the hairs on their skin. The rift itself was mesmerizing—an unnatural split in the space around them, glowing with an ethereal light that made it hard to look away.

"What do you think it is?" Gon asked, his voice filled with a mixture of wonder and excitement.

Killua's instincts screamed at him to retreat, but he knew there was no chance of that happening. "I don't know, but it's dangerous. We should report this to the Association—"

Before he could finish his sentence, the rift exploded with light. A powerful force surged from the tear, knocking both boys backward. Gon and Killua hit the ground hard, the impact rattling their bones. For a moment, the world went white, and all they could hear was the deafening hum of energy.

When the light finally faded, Gon opened his eyes. His head throbbed, and for a second, he couldn't tell if the world had stopped spinning. Slowly, he pushed himself up onto his elbows, blinking as his vision cleared.

But something was wrong.

The thick jungle of the NGL was gone. Instead, towering pine trees surrounded them, their branches swaying gently in the cool breeze. The air was different too—crisp and clean, with the scent of pine needles filling his lungs. The temperature had also dropped significantly, the muggy humidity replaced with a refreshing chill.

"Killua?" Gon called, his voice still hoarse from the shock.

"I'm here," came Killua's voice from nearby. The white-haired boy was already on his feet, dusting himself off. His silver eyes scanned their surroundings with an intensity that made it clear he was on high alert. "Where the hell are we?"

Gon stood up, wincing slightly as he rubbed his shoulder. "This isn't the NGL…"

"No kidding," Killua muttered, his eyes narrowing. He could feel it again—that strange pulse in the air. Only now, it was different, more pronounced. Whatever energy had pulled them through the rift was still present, but there was something else too—something dark and malevolent lurking in the shadows.

Before either of them could make sense of their surroundings, there was a rustling in the bushes ahead. Both boys tensed, prepared for an attack. Killua's hands crackled with electricity, his body subtly shifting into a battle stance, while Gon's fingers hovered near his fishing rod.

The rustling grew louder, and from the shadows, a figure emerged—a boy around their age, dressed in a strange green checkered haori. His black hair was tied back, and a calm but serious expression rested on his face. He carried a sword at his side, but it wasn't drawn. Behind him, another figure appeared—a girl with dark hair and a bamboo muzzle covering her mouth. Her eyes were soft, yet there was something undeniably dangerous about her presence.

The boy in green stopped when he saw Gon and Killua, his brow furrowing slightly as if he hadn't expected to see them here.

"Who are you?" Gon asked, his voice bright with curiosity despite the tension in the air.

The boy in green hesitated for a moment, clearly assessing whether the two strangers were a threat. Finally, he spoke. "I'm Tanjiro Kamado. This place… it's not safe. You need to leave. There's a demon nearby."

Killua scoffed, folding his arms. "A demon? What's that supposed to mean?"

Tanjiro's expression grew serious. "It's not something to joke about. Demons are dangerous creatures that feed on humans. I'm part of the Demon Slayer Corps, and our job is to protect people from them."

Gon's eyes lit up with excitement, as if the idea of demons was the best thing he'd heard all day. "A demon, huh? That sounds awesome! We should help you!"

Tanjiro blinked, clearly taken aback by Gon's enthusiasm. "Help…?"

Killua rolled his eyes. "What Gon means is, we've dealt with dangerous creatures before. This shouldn't be a problem."

Before Tanjiro could respond, the ground beneath them began to shake again, only this time it wasn't caused by the rift. From the shadows of the trees, a low growl echoed, and the temperature around them seemed to drop even further. The air felt heavy now, thick with the ominous presence of something dark and hungry.

Tanjiro's hand went straight to the hilt of his sword. "It's here…"

The demon emerged from the darkness, its grotesque form towering over the group. Its skin was pale and stretched tight over bulging muscles, its eyes glowing with a ravenous hunger. Sharp claws gleamed in the dim light as it opened its mouth, revealing rows of jagged teeth.

It moved fast, far faster than any normal human could react to, but Gon and Killua were no ordinary humans. In an instant, Killua activated Godspeed, his body crackling with lightning as he zipped to the side, narrowly avoiding the demon's claws. Gon, equally fast, ducked low and rolled to the side, landing beside Tanjiro, who had already drawn his Nichirin Blade.

Tanjiro's eyes were focused, calm despite the danger. He inhaled deeply, centering himself. "Water Breathing, First Form… Water Surface Slash!"

With a swift, fluid motion, Tanjiro sliced his blade through the demon's neck. The creature's head hit the ground, and its body began to dissolve into ash. For a moment, silence filled the clearing.

Gon's eyes were wide with amazement. "That was incredible! You took it down in one hit!"

Tanjiro sheathed his sword and glanced at Gon and Killua. "You're strong, but demons are dangerous. Only a Nichirin Blade can kill them. You should be careful."

Killua's silver eyes narrowed. "Looks like we're not in our world anymore…"