The exit of the tunnel was not a reprieve; it was a transition from a claustrophobic tomb into a damp, suffocating purgatory.
As the remaining applicants emerged from the subterranean darkness, they were swallowed by the Numere Wetlands—the "Swindler's Swamp." A thick, cloying mist hung over the landscape like a shroud, smelling of ancient rot and stagnant water. Gnarled trees reached out of the muck like the skeletal fingers of drowning giants, and the very ground beneath their feet felt like it was breathing.
"This is where the real filtering begins," Satotz announced, his voice drifting through the fog with a ghostly resonance. "The creatures here specialize in deception. They will mimic your friends, prey on your senses, and lead you to your doom. If you lose sight of me, you will likely never be seen again."
Leorio stood at the edge of the marsh, his tall frame silhouetted against the grey, diffused light. He took a long, steadying breath. He wasn't looking at the mist; he was looking inward, at the intricate biological machine he had spent years perfecting.
Internal Monologue: This isn't just a swamp. It's a massive, open-air petri dish of predators. If I rely on my eyes, I'm dead. If I rely on my ears, I'm dead. I have to rely on the pressure.
"Total Concentration... Constant," Leorio whispered.
His lungs expanded to their absolute limit, pulling in the damp air and filtering it with mechanical efficiency. His heart rate slowed to a rhythmic thrum, sending hyper-oxygenated blood to his brain and limbs. To any normal observer, he just looked like a man standing still. But to the "monsters" in the crowd, the atmosphere around him had suddenly shifted.
In the distance, Gittarackur—the pin-covered monstrosity that was actually Illumi Zoldyck—tilted his head with a series of rhythmic, mechanical clicks. His soulless, needle-like eyes fixed on Leorio's back. He sensed a predator. Further away, Hisoka's tongue flicked over his lips, his golden eyes narrowing in sudden, sharp interest. The "delicious" pressure he had sensed earlier wasn't a fluke; it was a feast.
Internal Monologue: I can feel them. Hisoka and Illumi. They're the only ones here who understand the shift. They can't see my aura because I'm keeping it tightly contained in 'Ten', but they can feel the biological 'noise' of my body falling silent. I'm a high-voltage wire that's just been insulated. Now, let's see who's hunting whom.
"Stay close to me," Leorio commanded, his voice dropping to a frequency that cut through the muffling fog. "Gon, Kurapika—don't trust the lights, and don't trust the voices in the mist. Trust the sound of my footsteps. I won't lead you astray."
The run through the swamp was a descent into chaos. The "Man-Faced Apes" and "Giant Mushrooms" began their grisly work, picking off the stragglers with terrifying efficiency. Screams echoed through the mist, cut short by the wet, sickening crunch of bone.
Leorio ran with his hand resting on the hilt of his katana. He didn't need to see Satotz's purple suit. He expanded his En.
En: 125 meters.
The shimmering sphere of his intent rippled outward, a 125-meter radius of absolute perception. Within this zone, Leorio was a god of information. He could feel the flutter of a dragonfly's wings on a reed, the ripple of a swamp-leech in the mud, and the erratic, terrified heartbeats of the examinees around him.
But most importantly, he could feel the cold, sharp void that was Hisoka.
The clown had stopped. He was surrounded by a group of examinees who had decided, in their infinite lack of wisdom, to "take out the dangerous one" while the mist provided cover.
"I'll be the judge," Hisoka's voice drifted through the trees, dripping with a murderous, almost sexual boredom.
Leorio skidded to a halt. The mist swirled around him, but his En told him exactly where the core group was.
"Gon, Kurapika, keep going. Follow Satotz's rhythm. Don't stop for anything," Leorio ordered.
"But Leorio—!" Gon started, his honest face twisted with worry.
"Go!" Leorio barked, the authority of a Chief Surgeon in his voice. "I'll catch up. There's a tumor back there that needs to be addressed before it spreads to the rest of the group. If I let him play his game now, he'll cull the people we need later. Go!"
Kurapika grabbed Gon's arm. He looked at Leorio, seeing the absolute, icy calm in the doctor's eyes—a gaze that belonged on a battlefield, not in a hospital. "Don't die, Leorio. That's an order from a friend."
As they disappeared into the fog, Leorio turned around. He walked back toward the clearing where the scent of blood was already thickening.
Hisoka stood in the center of a circle of fresh corpses. He was holding a blood-stained card, his body vibrating with an unsatiated hunger. When Leorio stepped into the clearing, the clown's eyes lit up with a terrifying radiance.
"Oh... the tall doctor," Hisoka purred, his voice a low, melodic growl. "I was wondering when you'd stop hiding that delicious pressure. You've been so... disciplined. But the mask is slipping, isn't it? I can see the hunter beneath the white coat."
Leorio didn't answer immediately. He took a wide, stable stance, his feet sinking slightly into the soft, treacherous earth. He let his suitcase drop into the mud.
"You're playing a game you don't understand, Hisoka," Leorio said. "These people are applicants. You're treating them like cattle in a slaughterhouse."
"They are cattle," Hisoka laughed, and then his aura suddenly exploded. He wasn't hiding it anymore. A thick, viscous shroud of Nen—his Ren—erupted from him. It was a dark, sticky energy that felt like being submerged in hot tar. It was the aura of a man who had forgotten the meaning of mercy.
Hisoka's Nen capacity was staggering. He could likely hold this level of output for five, maybe ten hours. By contrast, Leorio knew his own limits. He was a neurosurgeon, not a powerhouse. His total Nen pool was smaller; he could maintain a full-power Ren for about three and a half hours before hitting the wall of metabolic exhaustion.
But Leorio had a bridge that Hisoka didn't. He had the bridge between the spiritual and the biological.
"Water Breathing, Tenth Form: Constant Flux," Leorio whispered.
He didn't just flare his aura. He integrated it. He synchronized the flow of his Nen with the rhythmic expansion of his lungs. He forced the energy to follow the pathways of his blood, coating his muscles from the inside out.
[SYSTEM ALERT: AURA AND BREATHING TECHNIQUE COMBINED. PHYSICAL OUTPUT MULTIPLIER: 4.0x]
The ground beneath Leorio's feet cracked. The air around him didn't just shimmer; it distorted under the sudden thermal output of his body. By forcing his aura to follow the pathways of his Total Concentration Breathing, Leorio's muscle fibers tightened to a density that shouldn't have been biologically possible. His speed and strength didn't just increase; they multiplied.
Hisoka's grin widened until it looked physically painful. "Exquisite! Your aura is small compared to mine... but the density! The strength! Are you an Enhancer, Doctor? Or are you something... stranger?"
In a flash, Hisoka moved. He didn't run; he vanished. He reappeared inches from Leorio's face, a card infused with Shu aimed directly at the doctor's jugular.
Clang!
Leorio didn't draw his sword. He didn't need to. He used the scabbard of his katana to parry the strike. The impact sent a shockwave through the clearing, blowing the mist away in a perfect, hundred-meter circle. Hisoka's eyes widened. He had put enough force into that strike to decapitate an elephant, yet Leorio hadn't moved an inch.
Internal Monologue: He's fast. But with my 'En' and the Water Breathing sharpening my synapses, his movements look like he's wading through honey. I can see the twitch of his deltoid before he even thinks about moving his arm. His 'intent' is as loud as a gunshot
Leorio pivoted, his movement a blur of surgical efficiency. He delivered a palm strike to Hisoka's chest. It wasn't a punch; it was a targeted application of kinetic energy.
"Water Breathing, Third Form: Flowing Dance!"
Hisoka flew backward, his body skipping across the swamp water like a flat stone. He twisted in mid-air with impossible agility, landing on a gnarled tree trunk and clinging to it like a predatory spider. He was coughing, a thin trail of blood leaking from the corner of his mouth. His ribs were groaning.
"Wonderful!" Hisoka screamed, his voice cracking with a manic delight. "More! Give me more! Break me, Doctor!"
He lunged again, this time throwing a dozen cards in a complex, overlapping pattern. Each was infused with Shu, turning them into projectiles that could pierce tank armor.
Leorio finally drew his blade. The steel hummed as it left the scabbard.
"Water Breathing, Sixth Form: Twisting Whirlpool!"
He spun his body in a fierce, vertical circle. The katana became a shimmering wall of steel. The cards were not just blocked; they were parried and redirected back at Hisoka with double their original velocity.
Hisoka flicked his wrist, his Bungee Gum—invisible to everyone but the Nen users in the swamp—snatching the cards out of the air. He landed on the ground, his chest heaving, his face contorted in a mix of agony and ecstasy.
"You're stronger than me... physically," Hisoka noted, his voice trembling with excitement. "That breathing... it's forced your body past its evolutionary limits. But how long can you keep it up, Doctor? My 'Bungee Gum' has already attached to your shoulder while we were 'dancing'."
Leorio looked at his shoulder. He couldn't see the pink strands of aura, but he was using Gyo on his eyes. He saw the shimmering, elastic thread clearly.
"You think I didn't notice?" Leorio said, his voice flat. "I've been tracking your aura signatures since the moment I stepped into this clearing. You're a magician, Hisoka. But I'm a surgeon. I know how to find the things that try to hide in the dark."
He reached out and grabbed the invisible strand with his bare hand. He didn't use Nen to pull it; he used pure, raw physical strength enhanced by the 4.0x multiplier.
"If you want to be close to me so badly," Leorio said, his eyes flashing with a cold, terrifying light, "then come here. Let's finish the consultation."
He yanked.
Hisoka, caught off guard by the sheer, overwhelming power of the pull, was yanked off his feet. He flew toward Leorio like a puppet with its strings cut.
Leorio met him halfway with a knee to the solar plexus, followed by a downward strike with the hilt of his sword.
BOOM.
The impact created a five-meter crater in the mud. Hisoka lay there, his ribs shattered, his breathing ragged and wet. He was laughing—a hacking, broken sound.
"You... you really are... a masterpiece," Hisoka wheezed. "You could kill me right now. Why don't you? Is it your 'oath'?"
Leorio stood over him, the glow of his aura slowly receding as he shifted back to a lower output. He was feeling the strain; his muscles were hot to the touch, and his heart was hammering against his ribs like a trapped bird. He knew he could hold this "monster" state for maybe another three hours if he pushed it, but the recovery would be brutal.
"Because I'm a doctor," Leorio said, his voice like falling ice. "I don't kill unless there's no other way to save the patient. Right now, you're not a threat. You're just a broken toy. If you stay in this crater and mind your business, I'll let you live to see the next phase. If you get up and follow my friends... I'll perform a lobotomy with this katana. Do you understand?"
Hisoka stared up at him, his golden eyes reflecting the sheer, uncompromising will of the man standing above him. For the first time in his life, Hisoka felt something akin to genuine, primal fear. It wasn't the fear of death—it was the fear of being truly outclassed. It was delicious.
"I understand... Doctor," Hisoka whispered.
In the shadows of the trees, two figures stood watching. Gon and Kurapika had doubled back, unable to abandon their friend. They had seen the entire exchange—the crater, the speed, and the way the "invincible" Hisoka had been dismantled.
Leorio turned his back on the clown and walked toward them. He moved with a steady, tireless jog. When he reached them, his face was a mask of calm, though his trench coat was torn and stained with swamp mud.
"Leorio! You're okay!" Gon cried, nearly tackling him. "We saw it! You were so fast!"
"Just some swamp gas and a bit of a disagreement," Leorio said, ruffling the boy's hair. "Nothing a doctor can't handle."
Kurapika looked at him, his eyes lingering on the katana. He saw the way the mud had been vaporized off the blade. "And the clown?"
"He's taking a nap," Leorio said shortly. "He won't be bothering us for the rest of the phase. He's... reconsidering his career choices.
Kurapika nodded, though the suspicion in his eyes remained. He knew Leorio was hiding a level of power that didn't make sense for a nineteen-year-old student. But he also knew that Leorio was the only thing standing between them and the true monsters of this world.
"We have to hurry," Kurapika said. "The examiner is almost at the end of the wetlands. My En—I mean, my senses—tell me the gate is close."
They reached the end of the swamp just as the mist began to lift, revealing a massive, ornate gate. Guarding it were two individuals who looked like they belonged in a different story—the giant Buhara and the sharp-eyed Menchi.
Satotz was standing there, checking his pocket watch. As Leorio, Gon, and Kurapika crossed the finish line, the examiner offered a small, respectful nod to Leorio.
"Number 403," Satotz said. "I see you've encountered the 'fog' of the wetlands. You seem... remarkably composed for someone who stayed behind."
"I have good lungs, Examiner," Leorio replied, his face a mask of exhaustion and resolve.
Internal Monologue: That was close. If I had stayed in that 4.0x state for another hour, I would have started to see muscle tearing and metabolic acidosis. I need to be careful. I'm stronger than Hisoka in a short-term physical contest, but his Nen endurance and versatility are still superior. If I want to win the long game, I need more than just 'Water Breathing'. I need an ability that doesn't rely on my Gate of Otherworlds. Maybe the Jujutsu world has the answer... Black Flash or Reverse Cursed Technique. I need a way to heal while I fight.
He looked back at the swamp. A few minutes later, a limping, battered Hisoka emerged from the mist. He was covered in mud, his face was bruised, and he was clutching his side. The other examinees stared in horror. Who could have done that to the Magician?
Hisoka's eyes found Leorio in the crowd. He didn't glare. He didn't threaten. He simply licked the blood from his lip and offered a small, twisted bow of respect.
"Leorio-san," Gon whispered. "Why is Hisoka looking at you like that? It's creepy."
"He probably just likes my coat, Gon," Leorio said, leaning against a tree. "Now, let's see what's for lunch. I'm starving."
As Menchi stepped forward to announce the start of the Second Phase—the cooking trial—Leorio felt the System in his mind chime again.
[NOTICE: NEW WORLD 'JUJUTSU KAISEN' ACCESSIBLE IN 22 DAYS.]
Leorio closed his eyes, taking a long, deep breath. He had protected the "future" of this world, but he knew the stakes were only going to get higher. He was a doctor in a world of monsters, and he was starting to realize that to save the world, he might have to become the biggest monster of them all.