The next day.
Sosuke did not go to learn the [Transformation Jutsu].
Because he couldn't get out of bed.
Genzo's combat training was not a game. Although he managed to dodge the final strike using the [Substitution Jutsu], the dozen or so rocks he took before that had struck muscle and bone with brutal, unyielding force.
By dawn, Sosuke felt as if he had been run over by a carriage.
Every joint, every muscle fiber screamed in protest.
He lay in bed, staring at a moldy corner of the ceiling. He tried to roll over, only to draw a sharp intake of breath as pain flared.
'This is the price.'
Sosuke smiled in self-mockery.
He struggled to his feet and cooked a pot of salamander meat alongside some rice porridge. The thermal energy from the ninja beast's meat radiated through his stomach, mildly alleviating his muscle spasms.
But he knew he wouldn't make it to the scrapyard today.
That was fine.
Genzo had said it himself: only a properly conditioned body could bear the burden of chakra. Haste makes waste.
Yet, he still insisted on opening the clinic.
It was a matter of posture. A calculated signal, whether to the Takaya Merchant Guild or the Uchiha Military Police Force.
He needed to project a specific kind of stability: 'I am here, and I will always be here.'
In this volatile shinobi world, stability was the highest form of credibility.
Sosuke pulled himself fully out of bed.
Every movement was accompanied by the wail of torn muscle fibers. His thighs and back suffered the most—those were the areas Genzo's rocks had hammered hardest during yesterday's [Substitution Jutsu] drills.
He checked his reflection in the mirror.
His left eye socket was still bruised purple. The massive welt on his forehead had subsided slightly, but it remained red and swollen.
"With a face like this, I look less like a doctor and more like a street thug who just caught a beating," Sosuke muttered with a bitter smile.
He applied a hot towel to his face.
Then, he retrieved a custom-made jar of "foundation" from beneath the counter. It was a crude mixture he'd synthesized using pearl powder and animal fat.
While it couldn't entirely conceal the contusions, it at least made him look less pathetic.
After all, a doctor needed an aura of authority. Even a black-market one.
Sosuke opened the door and hung up the open sign.
The sunlight was a bit glaring. People drifted through the streets, most of them commoners with malnourished, sallow faces.
A small queue had already formed outside.
"Dr. Sosuke, your face..." the older woman at the front of the line stared at him in surprise.
"Took a bad fall gathering herbs last night," Sosuke lied without a change in expression.
"You went into the mountains? Oh my, you need to be careful. I hear the mountains haven't been peaceful lately."
"Indeed. Come on in."
The treatment began.
Cleanse, disinfect, bandage, collect the money.
His movements were mechanical and highly proficient. Internally, however, Sosuke's brain was operating at high speed.
He was mentally reviewing yesterday's training.
The crux of the [Substitution Jutsu] lay in the precise timing of the chakra burst. Too early, and the enemy would simply change their attack trajectory. Too late, and he would take the hit.
This microsecond-level perception couldn't be achieved through rote repetition alone. It demanded superior neural reaction speeds.
'I need to keep eating the Fūri liver.'
Sosuke made his decision.
Even though the organ contained toxins, and even though swallowing it felt like ingesting razor blades, the physiological results were undeniable. To grow stronger, this level of agony was nothing.
By dusk, the final patients had scattered.
Sosuke locked the clinic door, his lower back aching as if it were about to snap.
He retrieved the Fūri liver.
Only one and a half remained. He sliced off a small piece, submerging it in strong liquor just as before.
The nauseating, metallic stench of blood permeated the air.
"Endure the bitterest of pain."
Sosuke closed his eyes and swallowed the liver.
A familiar agony erupted in his stomach, sharp as a scalpel scraping against his insides.
This time, he didn't tremble.
Habit was a terrifying force. His nervous system was already adapting to the pain signals, reframing them as biological feedback that his body was actively upgrading.
He sat cross-legged, guiding that flow of cyan chakra throughout his entire body.
Soon, piercing through the pain, he felt a faint chill. It was a physiological marker—the wind-natured chakra was actively restructuring his constitution.
The night passed in silence.
The next morning.
Sosuke arrived at the scrapyard once again.
His injuries hadn't fully healed, but they no longer impeded his mobility.
"Your injuries recovered this fast?"
Genzo watched Sosuke approach, a hint of surprise in his eyes.
Given that volume of training, an ordinary person would be bedridden for at least three days. This kid's regenerative capability was slightly abnormal.
"Got lucky. Took some tonics," Sosuke deflected casually.
"Hmph. Rich kid."
Genzo didn't pry. In the shinobi world, as long as you had the money, you could indeed purchase a variety of secret medicines to drastically shorten recovery times.
"Today, I'll teach you the final one—the [Transformation Jutsu]."
Genzo pointed to a large boulder nearby.
"The [Transformation Jutsu] is both the hardest and the easiest of the E-rank ninjutsu."
"It's easy because it requires very few hand seals. Dog, Boar, Tiger."
"It's hard because it doesn't test your chakra—it tests your observation skills."
Genzo picked up a stone from the ground.
Poof.
White smoke flashed.
A second, identical stone appeared in Genzo's hand.
Down to the grain, the moss, and the micro-fractures on its surface, the two were utterly indistinguishable.
"This is object transformation."
Genzo released the jutsu.
"If you want to transform into a human, the variables become infinitely more complex."
"Height, weight, scent, gait, and even vocal cadence."
"An average [Transformation Jutsu] only fools the eyes. Any shinobi with a shred of combat experience can see through it by catching a whiff of your scent or glancing at the shadow you cast."
Genzo looked at Sosuke.
"You possess a sharp eye for observation. I noticed when you cast the [Clone Jutsu], your attention to detail is flawless."
"But the [Transformation Jutsu] operates on entirely different principles. A clone is a fabricated illusion; you are a physical entity. The [Transformation Jutsu] acts as a chakra cloak layered over your actual body."
"If your transformation is too fat, your physical arms won't actually be able to reach the opponent. If your disguise is too short, your real feet will still be rooted in the ground."
"This is known as physical interference."
Sosuke nodded.
It was akin to wearing a mascot suit. If the suit was disproportionately large, your biomechanics would distort to compensate.
"Try it," Genzo said. "Transform into me."
Sosuke took a deep breath.
Dog—Boar—Tiger.
Chakra surged.
He mentally constructed Genzo's profile.
Decadent, one-legged, reeking of cheap alcohol, with filthy, unkempt hair.
"[Transformation Jutsu]!"
Poof.
The smoke cleared.
A second "Genzo" stood in the clearing.
The visual replica was highly accurate. He had even managed to simulate the empty, flapping pant leg.
But Genzo only needed a single glance before he let out a harsh sneer.
"Where's your leg?"
Genzo swung his iron crutch, striking the exact spot of the amputated leg on Sosuke's disguise.
Although the space appeared empty, the iron crutch collided with a dull thud.
It had struck Sosuke's real leg. The jutsu was merely utilizing light refraction to render the limb invisible.
"If this were a real battlefield, an enemy slashing at that opening would expect their blade to hit air. Instead, they'd hit raw meat."
"That is a fatal flaw."
Sosuke released the transformation.
"How do you solve this physiological discrepancy?"
"Skeletal compression. Or utilizing posture to obscure your true physical dimensions."
Genzo demonstrated.
Suddenly, he curled inward, transforming into a young child barely half a meter tall.
His skeletal structure hadn't literally shrunk. Instead, he employed an extreme contortionist posture, tightly folding his long limbs against his torso under the visual cover of the jutsu.
"The [Transformation Jutsu] paired with body modification arts creates a flawless disguise."
"Of course, that is too early for you."
Genzo stood back up, reverting to his original form.
"Master the surface level first. At the bare minimum, you must ensure that as long as no physical contact is made, the visual deception remains absolute."