The year on Mount Sagiri had been a symphony of steel, frost, and oxygen.
Leorio stood at the trailhead, looking back at the small wooden hut that had been his home for twelve months. He looked different—not just the height or the muscle, but the way he carried himself. He moved with a predatory stillness, his 193 cm frame no longer seeming ungainly, but rather like a coiled spring of immense tension.
He had outclassed Tanjiro within months. It wasn't just the physical head-start; it was the neurosurgeon's mind. While Tanjiro had to learn the "feeling" of the Water Breathing, Leorio had mapped the physiological mechanics of it. He understood exactly which muscles to relax to allow the blood to flow faster, and which nerves to fire to achieve the "Flow."
He had mastered all ten forms of Water Breathing. Sakonji Urokodaki had eventually stopped teaching and started observing.
"You are ready for the Final Selection, Leorio," the old man had said a week ago, his voice heavy with a mix of pride and confusion. "In fact, you have surpassed the requirements. But Tanjiro... he still needs time. Perhaps another year of splitting the rock."
"I won't be going to the Final Selection, Sakonji-san," Leorio had replied, bowing low. "My path lies elsewhere. But the lessons of the water will stay with me forever."
He didn't just spend the year breathing. Whenever his body reached its limit, he sat in Zetsu, practicing the advanced applications of Nen. He wasn't a prodigy—he couldn't manifest complex Hatsu out of thin air—but his discipline was absolute. He had ground his way to an intermediate level in Gyo (focusing aura to the eyes), En (extending aura to sense surroundings), and Shu (shrouding an object in aura).
Now, he was ready.
Internal Monologue: Time to go home. I have the lungs of a Hashira, the hands of a surgeon, and the aura of a Hunter . Let's see how the 287th Exam handles a Leorio who knows how to breathe properly.
"System," he whispered. "Return."
The transition was violent.
The cold, snowy air of Taisho Japan was replaced by the humid, salty breeze of the Yorbian continent. Leorio stumbled as he hit the mountain peak where he had first opened the Gate.
[NOTICE: RETURNING TO PRIMARY WORLD. INITIATING 24-HOUR ZETSU PENALTY.]
He felt his aura snap shut. The "Water Breathing" strength remained—his muscles were still hyper-oxygenated and dense—but the spiritual shield was gone. He felt naked. Vulnerable.
He didn't linger. He began the 40 km trek back to Yucanto.
When he reached the orphanage, the sun was setting. He looked like a ghost. His long hair was tied back in that sharp Eren-style bun, he was wearing a dark, rugged haori over his clothes, and strapped to his waist was a Nichirin sword—not a legendary black blade, but a fine, sturdy steel that hummed with the memory of the mountain.
"Leorio?"
Sister Maria dropped her basket of laundry. The other children stopped playing, staring up at the giant who had just walked through the gate.
"You're back!" one of the younger boys screamed, sprinting toward him. "We thought the bears got you!"
Leorio caught the boy with one arm, a genuine, tired smile breaking across his face. "Bears? They tried, kid. But I'm harder to chew than I look."
The sisters crowded around him, their faces etched with worry. In this world, eighteen was the age of "graduation"—the age when you had to leave the orphanage and find your own way. They had feared he had left without saying goodbye.
"I went to the mountains to train," Leorio explained to Sister Maria, his voice sounding deeper, more grounded. "I needed the silence to... find my path."
"You look like you found a mountain and moved it," she whispered, looking at the sheer breadth of his shoulders. "Where did you get that sword?"
"A gift from a teacher," Leorio said. "Sister, I have the Hunter Exam tomorrow. May I stay one last night?"
"Of course, Leorio. You will always have a place here."
That night, Leorio brought out the last of the salted meat he had hunted before the jump—huge slabs of mountain boar. He watched the children eat, his heart aching with a strange mix of Aris Thorne's cynicism and Leorio's empathy. He was doing this for them. Every step he took toward the Hunter License was a step toward building a hospital that would ensure no kid in Yucanto ever died of a preventable fever again.
Leorio woke up before dawn. The 24-hour Zetsu penalty had lifted.
As he sat up, a series of notifications flashed before his eyes.
[CONGRATULATIONS ON COMPLETING YOUR FIRST WORLD TRAVEL.]
[REWARD: INTERMEDIATE-ADVANCED NEN APPLICATION MASTERY.]
[DETECTION: HOST ALREADY POSSESSES INTERMEDIATE-INTERMEDIATE MASTERY.]
[UPGRADING REWARD... CONGRATULATIONS! YOU HAVE ACHIEVED COMPLETE MASTERY OF ADVANCED NEN APPLICATIONS (GYO, EN, SHU, KO, KEN, RYU).]
A massive influx of "muscle memory" flooded his nervous system. Suddenly, the way he held his aura felt as natural as breathing. He didn't just know how to use Shu; he felt his sword become a literal part of his arm. He didn't just know En; he could feel the heartbeat of every bird in a 50-meter radius without even trying.
"Complete mastery," Leorio whispered, his eyes glowing with a faint, blue-white light. "This changes everything. I'm no longer just a 'strong guy.' I'm a combatant."
He stood up and strapped the katana to his side. He checked his suitcase—the iconic Leorio suitcase—now reinforced with steel and containing his medical supplies.
[NEW WORLD UNLOCKED: JUJUTSU KAISEN]
Leorio stared at the text. Jujutsu Kaisen. Cursed energy. Domain Expansions. Sukuna.
"Not yet," he said firmly. "I have an exam to pass. And I have friends to meet."
He left the orphanage as quietly as he had arrived. He left a bag of Jeny—nearly everything he had earned from his "gutter-doc" clinic—on Sister Maria's desk with a note: For Pietro's memorial and the kids' winter coats. I'll send more once I'm a Hunter.
He walked toward the port of Yucanto, his 193 cm frame drawing stares from everyone he passed. He wasn't wearing a suit yet—he had a dark, high-collared coat that billowed behind him, looking more like a modern-day swordsman than a prospective doctor.
As he boarded the ship that would take him toward the first stage of the exam, he felt the familiar roll of the waves.
Internal Monologue: This is it. The 287th Hunter Exam. Somewhere on this boat, or perhaps at the next port, is a boy with a fishing rod and a boy with blonde hair and a debt of vengeance. I wonder if they'll recognize me. I wonder if the world is ready for a Leorio who doesn't just scream—but cuts.
He leaned against the railing, his hand resting on the hilt of his sword. He took a deep breath—a Total Concentration Breath—and felt the oxygen sharpen his senses.
"Let's see what this world has to offer," he muttered.
The ship's horn wailed, signaling the start of a journey that would change the history of the Hunter Association forever. The Doctor had arrived, and he brought the sting of the cold mountain air with him.