Lesson in Nen

Killua and Gon kept a steady pace behind Satotz, their feet splashing through the mucky terrain of the Milsy Wetlands. The dense fog clung to their skin, cool and clammy, as the treacherous landscape loomed around them with its deceptive allure. Killua's sharp eyes scanned the shifting shapes in the mist, while Gon kept his gaze firmly fixed ahead, determined and unyielding. Both of them could feel something around the running crowd, a tension of something other than fear looming over participants and the source of the tension was ahead.

"Why are you even trying to become a Hunter?" Killua asked, his voice casual but tinged with genuine curiosity. "You're just a kid."

Gon glanced at Killua, a grin tugging at the corners of his mouth. "We're practically the same age," he said lightly. "I'm here because my dad's a Hunter. I want to find him and understand why he left me behind to be one. I guess... I want to see what he saw."

Killua snorted, though not unkindly. "That's pretty intense, wanting to become a Hunter just for that. Me? I'm not here to become one. I'm just in it because the competition seems fun." Killua's gaze darkened momentarily as he continued, his voice dropping to a warning tone. "But hear, have a piece of advice — you should stay away from that guy, Hisoka. I can feel his bloodlust from here. It's like he's barely keeping it under control."

Gon's eyes narrowed slightly, glancing over his shoulder in the direction where Hisoka trailed behind the group, his presence a menacing shadow amidst the other examinees. Before Gon could respond, a sudden commotion erupted from the rear and the looming tension of the crowd exploded. Many who were running beside each other got separated in crowd chaos.

A group of examinees, emboldened by the mist and driven by their desperation, veered away from Satotz's path. Armed with an assortment of weapons—knives, clubs, and spears—they spread out, moving in a coordinated circle around Hisoka. Their leader, a burly man with a spiked club, stepped forward, a malicious grin spread across his face.

"Look, clown," the leader sneered. "Satotz is getting further ahead. You won't find your way out of this misty hell without us. But we're not here to help you." He raised his club, pointing it directly at Hisoka. "We're here to make sure you don't make it to the end. This is for everyone you killed last time. Someone like you couldn't be allowed to become a hunter."

Hisoka's expression twisted into one of gleeful anticipation, his eyes lighting up with a dangerous spark. "Oh?" His voice dripped with mockery as he tilted his head, his hands playing idly with the deck of cards he carried.

"So, you're saying you'll be the exam proctors now?" His laughter echoed through the swamp, a sound that sent chills down the spines of those around him. "How delightful. Let's see if you're up to the task."

With a flick of his wrist, Hisoka unleashed his deadly cards, each one slicing through the air with lethal precision. The mist turned red as examinees fell, their bodies crumpling to the ground, throats slit and blood spilling into the muck. Hisoka moved like a phantom, his every motion fluid and terrifyingly efficient. He dispatched each opponent with a grin on his face, relishing in the chaos he wrought.

Amidst the carnage, Hisoka's gaze fell on a smaller group—Leorio, Kurapika, and examinee #53 Pokkle . The trio had tried to keep pace with Satotz, but now they found themselves cornered, Hisoka's looming figure blocking their path.

"We need to get out of here," Kurapika urged, eyes darting around for an escape route.

"Let's run towards different directions, each on his own, that way we have more of chance to survive," Pokkle suggested as he shivered in fear.

Kurapika gave a nod, then they turned and bolted, feet splashing through the swamp as they ran. But before they could make it far, someone's mood shifted and Leorio skidded to a halt, spinning around with a defiant snarl.

"I'm not running away! That guy was telling me Hisoka murdered his sister in the last exam. I am sorry, but I can't let this one get away," Leorio roared, fists clenched as he charged back towards Hisoka. "I fought deadly pirates to make my way here. Some clown isn't enough to scare me off."

Hisoka smiled. "A brave one to die."

Leorio swung wildly, desperation and fury fueling his attack. Hisoka, unfazed, dodged effortlessly, his grin widening.

"Don't ever underestimate me," Leorio snarled.

Just as Hisoka's fist was about to connect with Leorio, a fishing line shot out, wrapping around Leorio's torso and yanking him backwards, out of harm's way. Gon, panting and wide-eyed, pulled his friend back, but the moment of relief was short-lived. Hisoka's fist lashed out, striking Leorio with a single, bone-crunching punch that sent him sprawling into the mud, unconscious.

Gon's eyes blazed with fury. "Leorio!" he shouted, his voice cracking with desperation. He turned his gaze to Hisoka, the man who had toyed with his friends and charged forward, swinging his fishing rod with all his might. Hisoka's eyes gleamed with twisted amusement as he easily evaded Gon's strikes, his movements almost lazy in their precision.

Gon's attacks grew more frantic, each swing more reckless than the last, but Hisoka dodged them all effortlessly, barely breaking a sweat. Gon's frustration boiled over, his breathing ragged as he put everything into a final, desperate blow.

Hisoka caught the rod with a single hand, holding it in place with an almost gentle grip. "Impressive," Hisoka mused, his voice dripping with a dark appreciation. "You've got potential, boy." He released the rod and gave Gon a light push, sending him stumbling back. "You pass," Hisoka declared, his voice laced with a sinister mirth. "For now."

Gon, panting and shaking, stared up at Hisoka, his heart pounding with a mix of fear and anger. Before he could react further, Hisoka's walkie-talkie buzzed to life. He answered it with a casual flick of his wrist, listening for a moment before turning his gaze back to Leorio's unconscious form. Without another word, Hisoka hoisted Leorio over his shoulder and began to run away, disappearing.

Gon watched him go, the weight of failure settling heavily in his chest. His fists clenched at his sides, the sting of being dismissed so easily burning deeper than any physical wound. Hisoka's figure faded into the mist, leaving Gon behind in the eerie silence of the swamp, surrounded by the fallen and the echoes of his unspoken resolve.

Hisoka carried Leorio's unconscious body deeper into the misty wetlands, his footsteps eerily quiet against the damp ground. As the fog thickened, a tall figure stood ahead, unmoving—Gojo, waiting with a casual, almost amused expression. Hisoka's lips curl into a sly smile.

Before he could say anything Gojo said, "I knew those morons were going to jump on you from how they were looking at you, so I watched from the distance, but that guy you carrying wasn't one of them. He was with my group."

"Oh, it's his fault, but does it bother you though? You asked me to share all I know about Nen back in the tunnels," Hisoka says, voice laced with playful menace. "But I could tell you were itching for something more... a fight, perhaps?"

Gojo's Six Eyes flicker with a calculating gleam. "I'm not here just to trade punches, Hisoka. I'm here for information, and you're going to give it to me."

Hisoka chuckled, twirling a card between his fingers. "I never do anything for free. Who did you take down to qualify for this little dance?"

Gojo's gaze narrowed a sharp edge to his otherwise laid-back demeanour. "Fenwick, he is dead now," he states simply, watching for Hisoka's reaction. "He was on the ship coming here. If you heard of that nen user, consider him proof of my strength."

Hisoka's eyes widened with recognition, then narrowed as he processed the reveal. "Fenwick... that little bumblebee. Always buzzing around my fight list," Hisoka mused, twirling the card faster. "Killing him was no small feat despite him being an unripe fruit."

"You've heard of him, then?" Gojo pressed, ignoring the sinister way Hisoka's grip tightens on his card. "Good. That means you know I'm serious."

Hisoka laughed softly, the sound unsettling in the misty stillness. "Oh, I'm more than familiar. And you, Gojo, you've made things interesting. I'll tell you about Nen—after we fight." His gaze flicked to Leorio, still slumped unconscious over his shoulder. "Of course, the stakes are always more fun when a life's on the line. Wouldn't you agree?"

Gojo's expression remained unreadable, but his stance shifted slightly, as though preparing for anything Hisoka might throw his way. "Leorio isn't part of the deal," Gojo says firmly, but there's a calmness to his tone that suggests he's already calculated every possible move Hisoka could make.

Hisoka shrugged, smiling wider. "You think you get to decide the terms? Let's see if you can back that up." He dropped Leorio unceremoniously to the ground, his aura flaring as he readies for combat.

As Hisoka stepped closer, his expression grows more intense, eyes gleaming with sadistic amusement. "Nen is all about harnessing your aura—your life energy," he begins, voices silky and dripping with condescension. "It can extend your natural lifespan, but only if you're disciplined enough not to gorge on your life force. The basics—Ten, shrouding yourself with aura not letting it leak away, Zetsu, to close all nura nodes responsible for aura production in your body, but that will leave you defenceless, Ren, to let your aura explode outwards, enough to scare off non-nen user, and Hatsu—are essential. But Hatsu, now that's where it gets interesting. It's the personal expression of your aura, and it's a complicated subject... one I'll explain—if you survive."

Gojo's fingers twitched almost imperceptibly, and in an instant, he flicked an iron nail he had picked up, coated with his aura directly at Hisoka. The projectile whistled through the air, but Hisoka effortlessly intercepted it with a card, their collision resulting in a violent burst of aura that disintegrates both objects on impact. The shockwave ripples through the air between them, but neither combatant flinches.

"I already know the basics," Gojo said, his gaze unwavering. "You're going to have to do better than that."

Hisoka's smirk deepened, and without warning, he tossed Leorio's unconscious body straight at Gojo. Gojo sidestepped smoothly, but the distraction served its purpose—Hisoka closed the distance in a blink, launching a spinning kick reinforced with aura. Gojo ducked, his movements a fluid blur, narrowly evading the attack.

Recovering from the missed strike, Hisoka straightened, cards fanned out in his hand like an executioner's blade. "I'll give you a free lesson," he said as if humouring a child. "What you just saw was Shu—an advanced application of Ten. Shu lets you enshroud an object with your aura, making it an extension of your own body. My cards, for example—each one is an extension of me."

He flicked a card with a sudden burst of speed, aiming for Gojo's throat. Gojo's hand lashed out, intercepting the card mid-flight with a precise twist of his wrist, deflecting it away with an aura-coated finger. Hisoka's eyes flashed with dark delight.

"And that kick?" Hisoka continued, unfazed by Gojo's counter. "That was Ken. It's a more advanced state—an intensified form of Ren that multiplies the aura around your body tenfold. It's mostly used for defence but with the right application…" He leaves the sentence hanging, the implications clear.

Gojo regarded him with a mix of curiosity and calculation, his stance still relaxed yet ready. "Interesting," Gojo remarked, his tone a blend of intrigue and mild irritation. "But I'm not here for a lecture—I'm here for the details that matter. Do you want to fight? Fine. But don't waste my time with what I already know."

Hisoka chuckled a low, throaty sound that echoed ominously in the mist. "Very well, Gojo. If you insist on cutting to the chase…" His aura flares, more cards appearing between his fingers as if conjured from thin air. "Let's see if you're worthy of the real secrets."

Hisoka's smile widened as he started circling Gojo, his steps casual but predatory. "Since you're so eager to learn, let me show you another trick," he said, his voice smooth and taunting. "Gyo is an advanced application of Ren. It's all about focusing a larger-than-normal portion of your aura into one specific body part, boosting its strength. But of course, it comes with a drawback—while one part gets stronger, the rest becomes more vulnerable."

Hisoka's eyes flickered. "Gyo is often used on the eyes, enhancing your vision to see the aura and Nen constructs that are hidden with In, or even faint traces of aura that others might miss. You remember Fenwick, don't you? That little bumblebee was quite proficient in Gyo. Gave me a bit of trouble the last time we met. His eyes could pierce through most concealments."

He paused, gauging Gojo's reaction. Gojo remains impassive, his gaze locked on Hisoka, dissecting every word, every movement.

"Why don't you try it?" Hisoka suggests, his voice dripping with mock encouragement. "Use Gyo."

Without warning, Hisoka flicked his wrist, sending a flurry of cards towards Gojo. They shimmer for a brief moment, then vanish completely from sight. Hisoka had used In, concealing his aura around the cards so perfectly that they became imperceptible, even to the most trained senses.

Gojo's expression remains unchanged, his body still as a statue. Then, with a casual tilt of his head, he dodged the first card. His movements are smooth, and effortless, as if he's merely swaying in a gentle breeze. One by one, he evaded each invisible projectile, sidestepping, twisting, and moving just enough to avoid each lethal strike without breaking his stance.

Hisoka's grin falters for a split second, intrigued by Gojo's precision. "Interesting," he muses, a hint of genuine curiosity creeping into his voice. "You dodged without using Gyo. Are you just lucky, or is there more to you than meets the eye?"

Gojo finally spoke, his tone as calm and unbothered as ever. "I don't need Gyo to see your invisible attacks." He raises a hand, adjusting his eyemask slightly, his Six Eyes glimmering faintly beneath. "Your little tricks might work on others, but not on me."

Hisoka chuckled with amusement. "Well, aren't you full of surprises?" He stepped back, considering his next move. The playful killer within him is more than thrilled by the challenge that Gojo presents. "Looks like I'll have to dig a little deeper to get a rise out of you."

"In," he said, rolling the word off his tongue with relish, "is an advanced form of Zetsu. It's used to render one's aura completely imperceptible, even to other Nen users. Unlike Zetsu, In doesn't halt your aura flow—it simply hides it. Perfect for sneak attacks or simply keeping your cards close to your chest, quite literally. It can be however countered by using Gyo in the eyes."

Hisoka gleaming with predatory intent closed the distance between them in a split second, his fist hurtling toward Gojo's midsection with astonishing speed. The air around his punch crackles with a concentrated aura, and just as it seems destined to land a devastating blow, Gojo reacted. He leapt back, the punch making contact but far less effective than intended. Gojo's swift retreat disperses most of the force, though the impact sends a dull shockwave reverberating through his body.

Hisoka smirked, his fist still raised, aura crackling like static. "You're quick on your feet," he remarks, his voice laced with admiration and just a hint of menace. "But did you feel that? That was Ko."

He paused, savouring the moment as if lecturing a student on the finer points of an art form. "Ko," Hisoka began, "is an advanced combination of Ten, Zetsu, Ren, Hatsu, and Gyo. It's all about concentrating every bit of your aura into one specific body part. When I threw that punch, my aura was focused entirely on my fist. Ten keeps the aura from dispersing, Gyo concentrates it, Zetsu halts the flow everywhere else, and Ren amplifies it further. The result? A strike that's overwhelmingly powerful, both offensively and defensively, in that one spot."

He flexed his fingers, the aura fading from his fist. "But there's a catch," he continued, eyes narrowing slightly. "Ko makes that one part incredibly strong, but it leaves the rest of the body defenceless. A risky move, wouldn't you agree? And the output may have novice nen users exhaust their aura reserve quickly sending them in a state of shock or zetsu."

Gojo watched him intently, not missing a beat. The implications of such a technique are clear; its sheer potency is offset by the vulnerability it creates. Hisoka, ever the showman, doesn't seem concerned about the risks.

"Of course," Hisoka added, "there's a way to mitigate that weakness. It's called Ryu." He rolled his shoulder as if preparing for another strike. "Ryu is like the little brother of Ko—less potent, but more versatile. It's Gyo in a state of Ken, redistributing aura in real-time for offence and defence adjustments. With Ryu, you can allocate your aura, say 70% to your fist and 30% spread elsewhere, or 80% to your leg and 20% to block an incoming attack. The key is balance."

He stepped forward again, this time more measured, as if giving Gojo time to absorb the information. "Ryu lets you fine-tune your aura output on the fly, making it easier to damage someone even if they're using Ken. But," he says with a sly smile, "it's no easy feat. You have to not only control your aura with absolute precision but also gauge your opponent's aura at a glance. Even if you manage all that, the flow of aura can betray your next move if you're not careful."

Hisoka's stance shifted subtly, aura rippling as he demonstrated the fluid nature of Ryu. His presence was electric, a mix of unpredictability and calculated menace.

"So, Gojo," he taunted, voice dripping with anticipation, "let's see how well you handle your aura. Show me if you can keep up with these tricks, or if you'll just be another notch on my belt."

The tension between them thickened a palpable energy that seemed to warp the very air around them. Hisoka's aura pulsed with a deadly rhythm, his mastery of Ryu evident in the effortless flow of energy throughout his body. Gojo's expression remained impassive, but his eyes—those brilliant blue Six Eyes—narrowed slightly, analyzing every flicker of movement.

Hisoka lunged again, this time with a series of rapid strikes, each one a precise demonstration of Ryu's dynamic balancing act. Gojo moves in tandem, each dodge calculated, each shift in Hisoka's aura meticulously observed. The battle between them becomes a dance of intent and reaction, each testing the limits of their mastery over aura and the other.

"You're better than I expected," Hisoka admitted, his voice carrying a note of genuine delight. "But this is just the beginning. I hope you're ready to push your limits, Gojo because I have plenty more to show you."

Gojo's calm demeanour belied the fierce intensity of the clash unfolding around them. "Don't worry about me," he replies coolly, his aura shimmering faintly. "I'm just getting started."

Gojo's eyes flashed with determination as he propelled himself forward, using all the techniques he just learned, unleashing a rapid barrage of strikes at Hisoka. Each punch and kick is executed with precise intent, reinforced with aura, aiming to overwhelm Hisoka with sheer speed and force. But Hisoka, with a languid smile, deflected the attacks effortlessly, his movements graceful and unhurried. His limbs intercepted Gojo's strikes with pinpoint accuracy, each clashes resonating with the sharp hiss of aura against aura.

Amidst this flurry of motion, Hisoka's expression remained almost serene, his gaze never wavering. He didn't even seem to be exerting much effort; it's as if he's reading Gojo's moves before they even happen. As Gojo retreats momentarily, Hisoka allows his aura to surge outward, expanding in a sudden, palpable wave that floods the surrounding area.

"En," Hisoka stated calmly, the single word carrying a weight of mastery. "It's another advance technique where you extend your Ren beyond its usual bounds, then use Ten to contain and shape it. Most people can barely manage a two-meter radius, and even then, they struggle to maintain it under pressure. But me? I can stretch mine up to fifty meters without breaking a sweat."

As Hisoka spoke, Gojo saw the shift in the air—a tangible sense of presence that encircled them. Hisoka's En manifested as a near-invisible sphere that expands outward, encompassing a vast radius. Within this zone, every movement, every shift in the aura, is instantly sensed by Hisoka, creating a hyper-awareness that borders on omniscience. Hisoka's aura brushes against Gojo's skin like a faint, electric tingle, probing every inch of his being.

"In this state," Hisoka continued, his tone casual but edged with a predatory glint, "I can feel everything within my En. The shape of your aura, the tension in your muscles, even the slightest twitch of your fingers. It's like having eyes on the back of my head, but so much more. And it's not just awareness—it's control. I can respond to any threat from any angle, faster than you can blink."

Gojo narrowed his eyes, focusing intently. The sheer breadth of Hisoka's En is impressive, extending well beyond the confines of a typical battle space. But more than that, the seamless integration of En into combat is what sets Hisoka apart. Maintaining such an expansive field while actively engaging in a fight is no small feat; it requires not only an immense reserve of aura but also unwavering focus and precision.

"But there's a catch," Hisoka added, as if reading Gojo's thoughts. "En is exhausting. Maintaining this range takes a lot of energy, and the longer it goes on, the more it drains you. Most can't handle it in a real fight, but for me… well, let's just say I'm not most people."

Gojo watched, analyzing every flicker of Hisoka's aura, every subtle shift in his stance. He could sense the strain, the constant hum of exertion beneath Hisoka's outward calm. Yet, Hisoka wielded his En like a conductor leading an orchestra, each motion calculated, each response precise.

"You see," Hisoka continued, stepping lightly within his sphere of influence, "it's not just about the range or the awareness. It's about how you use it. In a fight, it's like having an extra sense—a sixth sense that gives you complete dominance over the battlefield. And you…" Hisoka's eyes narrowed slightly, his grin widening, "You're a fascinating opponent, Gojo. I wonder, can you match this level of mastery, or will you fall short?"

"You're impressive," Gojo admitted his tone even but laced with a hint of defiance. "But don't think for a second that I'm intimidated. Let's see how well you handle what's coming next."

Hisoka shrugged, his demeanour still tinged with that playful, almost mocking edge. "Well, that's the end of our little Nen lesson," he said, letting his aura relax just slightly, the En retracting back closer to him. "There are countless applications and combinations out there, each with its quirks and intricacies. But for now, you'll have to figure out the rest on your own."

Gojo watched him intently, eyes narrowing as he assessed every word. Hisoka's casual dismissal didn't go unnoticed—an acknowledgement that while Gojo has learned a lot, he's still just scratching the surface. For a moment, the two stand in a tense, silent standoff, the air thick with anticipation.

Then, Gojo sighs, a slow, deliberate exhale that echoes through the stillness.

"Everything that can be learnt has been learnt, for now. Finally," he mutters, a smirk playing at his lips as his hands reach up to his eyes. He slowly removes his black sleeping mask, revealing his piercing blue eyes that shimmer with an ethereal glow. "No more holding back."

The effect was immediate and palpable. His Six Eyes, now fully unleashed, blazed with a radiant intensity that seemed to cut through the very fabric of reality. The aura around Gojo flares like wildfire, a bright, shimmering expanse that stretches outward in all directions. His En burst forth, expanding rapidly, overlapping and disrupting the field that Hisoka had so meticulously crafted.

Hisoka's En shuddered under the pressure, like a soap bubble on the verge of bursting. The stability he once maintained with ease now wavers, Gojo's presence pushing against it with overwhelming force. It's as if a tidal wave has collided with a calm sea, the two forces battling for dominance, but Gojo's aura surges with an undeniable, relentless power.

Hisoka's smile faltered ever so slightly, the first hint of genuine surprise flickering across his face. He tried to maintain his En, pouring more aura into it, but Gojo's pressure was too much. His sphere began to retract, squeezed by the sheer might of Gojo's expanding domain.

Gojo stepped forward, his aura pulsing with every stride, each step like the beat of a war drum. The glow of his Six Eyes pierces through Hisoka's En, revealing every hidden aspect, every concealed nuance of Hisoka's Nen. Nothing escaped Gojo's sight; his vision cutting through the illusions and obfuscations, laying bare the truth of the battlefield.

"This is what true mastery looks like," Gojo says, his voice carrying an almost casual confidence that makes it clear—this is no longer a game. The En around him hums with a distinct, resonant frequency, vibrating the air and sending ripples through Hisoka's presence. The sheer density and clarity of Gojo's aura make it feel almost tangible, like a force of nature that Hisoka is powerless to resist.

Hisoka's lips curl back into a grin, a flicker of exhilaration sparking in his eyes. The thrill of facing a new challenge, of pushing against an insurmountable wall, is what he lives for. But even he has to acknowledge the sheer scale of Gojo's power.

"You're something else, aren't you?" Hisoka murmurs, his voice edged with genuine admiration. "Looks like I underestimated you, Gojo."

Gojo's gaze sharpens, his aura continuing to press down on Hisoka, pushing the other's En to its very limits. "And I haven't even started yet," he replies, his tone calm but carrying an unmistakable warning.

The clash of their En resonated, sending waves through the surroundings. Hisoka's cards trembled in his hands, the fine edges quivering under the onslaught of Gojo's energy. For the first time, Hisoka felt a hint of struggle as he tried to maintain his footing within Gojo's overwhelming domain.