As noon drew near, Shin set aside the scroll in his hands and began preparing lunch for himself.
Not long ago, Megumi had finally agreed to her son's request and stopped exhausting herself by preparing an entire day's worth of meals early every morning before leaving for work.
First, Shin didn't want his mother to be overworked. Second, reheated food always tasted far worse than something freshly made.
Having lived another life, Shin's outlook was simple. He trained relentlessly so that, while enjoying the wonders of the Ninja World, he wouldn't be casually killed by someone along the way.
He wanted a life different from his previous one—but he had no intention of becoming an ascetic monk, depriving himself of comfort and enjoyment.
Today's plan was simple: steamed fish.
Shin reached into the bucket in the kitchen, grabbed a live fish, and slammed it hard against the floor.
The fish, lively just a moment ago, was instantly stunned and felt the call of the Shinigami.
He placed it on the cutting board—but instead of processing it right away, Shin extended his right hand over the fish's body. A faint green chakra gradually formed around his palm.
This was a basic Healing Technique, a precursor technique to the A-rank medical ninjutsu known as the Mystical Palm Technique.
That green glow was Medical Chakra—a special form of chakra capable of stimulating cellular regeneration in injured tissue, thereby healing wounds.
Not all chakras can perform medical ninjutsu. Only a chakra with a Yang-leaning nature can produce healing effects.
As for how one cultivates it, the answer lies in precise chakra control.
Chakra, as every ninja knows, is produced by combining physical energy drawn from the body's cells with spiritual energy in roughly equal proportions. If the balance is off, the two energies fail to fuse, and the chakra cannot be refined at all.
That, however, is only the general rule.
To elevate chakra to a medical level and give it healing properties, one must precisely regulate that ratio.
A medical ninja increases the proportion of physical energy while reducing the proportion of spiritual energy during chakra refinement.
The resulting fused chakra possesses heightened vitality—this is the most basic form of Yang attribute training.
The higher the proportion of physical energy, the stronger the vitality, and the more effective the healing.
Herein lies the contradiction.
Reducing spiritual energy naturally weakens chakra control—yet medical ninjutsu demands extremely fine control. Wanting both at once is inherently difficult, which is why advanced medical ninjas are so rare.
Reversing the ratio—allowing spiritual energy to dominate—produces a basic Yin attribute, suitable for Genjutsu and certain secret techniques.
Thus, both Genjutsu specialists and Medical Ninjas require extraordinary chakra control. They must be able to refine chakra even when physical and spiritual energies are imbalanced—and control it with even greater precision.
This is not something an average ninja can manage. It demands immense patience and talent.
Of course, there are exceptions.
The Uchiha Clan is born with naturally strong Yin attributes, while the Senju and Uzumaki Clans possess exceptionally powerful Yang attributes.
Tsunade's status as the greatest medical ninja in the world has nothing to do with her appearance—it is the result of overwhelming Yang chakra and peerless control.
In the Ninja World, chakra control cultivation can be divided into stages.
The first stage is precise mastery—reducing waste, increasing efficiency, learning techniques faster, and maximizing power.
This is where the vast majority of ninjas spend their entire careers.
The second stage is the ability to stably refine chakra while actively modifying the ratio of physical and spiritual energy.
The greater the deviation that can be maintained, the deeper one's mastery of Yin and Yang attributes.
Shin was currently at this second stage.
This knowledge was not something found in Konoha's public records. Most ninjas didn't even possess the conceptual framework to understand it.
Shin had pieced it together through careful study and the knowledge he carried from his previous life.
As for the third stage, he had some preliminary hypotheses—but it was far too early to pursue them. Even fully exploring the second stage would take years of cultivation.
Back on the cutting board, there was no auxiliary scroll beneath the fish.
The kind of scroll Sakura once used under Tsunade's guidance—etched with stabilizing patterns to help beginners refine medical chakra—had been necessary when Shin first started. Now, he no longer needed it.
Under Shin's treatment, the fish revived, flopping around energetically, as if nothing had happened at all.
Then it was struck on the head with a knife and promptly died.
Fish: "???"
The chickens, ducks, geese, and rabbits that had previously suffered the same fate in the Higashino household offered silent agreement.
After eating, Shin headed out and used his mother's library card to enter the Konoha Library.
The books at home were limited; the library, by contrast, was a treasure trove. Lately, Shin spent most of his afternoons here, immersing himself in chakra theory.
The Konoha Library held extensive records: the nature and characteristics of elemental chakra, analytical breakdowns of Genjutsu effects, and countless summaries compiled from the experience of past generations.
When Tenten was trapped in the Infinite Tsukuyomi, she had consulted theoretical Genjutsu texts here.
The fact that her dream-self knew exactly where to go was proof enough that these books existed in reality—and that she had read them before.
Everything here was theory.
No hand seals. No practical techniques. No secret releases.
This wasn't some mystical archive where legendary arts were hidden inside mundane texts.
If Shin expected to stumble upon a forbidden ultimate technique between two dusty volumes, he would be sorely disappointed.
But for him, this knowledge was more than enough.
The training methods for any Ninjutsu, Genjutsu, or Taijutsu were guarded secrets of families and of the Village itself. To obtain them, one either had to exchange mission merit or take on a powerful master.
Most ninjas believed that learning a few powerful techniques was enough to become strong. They chased jutsu while neglecting the most fundamental theories beneath them.
This was especially true of those brats who dreamed of becoming Hokage, convinced that mastering several impressive Ninjutsu alone would carry them to the top.
Shin thought differently.
To him, the theoretical knowledge painstakingly summarized by generations of predecessors was the true treasure.
Techniques were merely the fruit—valuable, yes, but meaningless without the tree that produced them.
Time slipped by as Shin instinctively refined his second-stage chakra control while reading. Before he realized it, the sky had grown dark.
He didn't return home. Instead, he devoured several large bowls of ramen and then headed straight for Konoha Hospital, preparing for class.
His mother, Megumi, often worked late several nights a week.
During the day, she treated patients, and in the evening,s she taught part-time classes to rookie Genin who aspired to become Medical Ninjas.
The Ninja Academy offered only basic medical theory; anyone who wished to pursue the field seriously after graduation had to enroll at the hospital and learn while practicing.
This was the training system Tsunade had once proposed.
Lay the foundation at the Academy—then let experienced professionals guide the newcomers at the hospital.
The classroom was a hospital conference room specially converted into a teaching space. It resembled a Ninja Academy classroom, though slightly more compact.
More than a dozen students were already present, with noticeably more girls than boys.
The room wasn't full, a clear sign of how few people truly possessed the talent or patience required for Medical Ninjutsu.
Most of the students were clustered toward the front; after all, those who came here genuinely wanted to learn. No one was lazing around in the back by the window.
They were all young, wearing Konoha headbands—fresh graduates, most likely only a year or two out of the Academy.
When Shin entered, several of them glanced over in surprise at his age, but no one spoke. If he was allowed inside, that meant the hospital had approved him.
Shin scanned the room and noticed a three-person desk in the front row on the left with only two occupants—a boy and a girl. The girl sat in the middle, the boy in the outer seat.
Shin hopped neatly into the empty seat on the inside without hesitation.
"Hey, kid. That seat's taken."
Shin turned to look at the speaker and froze for a moment.
The boy appeared to be around ten years old, with short black hair. A pair of goggles rested over his eyes in addition to the forehead protector he wore.
"No way…" Shin muttered, leaning back slightly.
Sure enough, emblazoned on the back of the boy's clothes was the large fan crest.
This look—no doubt about it. Uchiha Obito.
And the girl in the middle? Brown hair like his mother's, purple markings on her cheeks, and a gentle and pure expression.
Nohora Rin. Without question.
Where there was Rin, Obito was never far behind. A devoted guardian through and through.
Obito coming to study Medical Ninjutsu? Please. He was just afraid his goddess would be stolen by someone else.
"Now, now, Obito," Rin said gently, stopping him. "Don't be so harsh. He's just a junior."
Shin, however, had no intention of indulging him.
"Am I not a person?" he asked calmly.
"Kid, you're pretty arrogant," Obito snapped. "You haven't even attended the Ninja Academy yet, have you? Coming here so young—do you even know what Medical Ninjutsu is?"
Seeing that Shin wasn't intimidated, Obito tried to expose him from a professional angle.
"Do you know how many types of blood vessels there are in the human body? The different characteristics of bleeding? The methods for stopping it?"
"Do you know how to clean a wound pierced through the palm by a kunai, and what precautions you need to take before using Healing Jutsu afterward?"
"Uh… that…?" Obito froze.
Academics were his mortal enemy. He clearly knew none of that. But he quickly found a new angle.
"So what if you know? You're still too young. Who gave you permission to attend this class?"
"My mom did."
"Your mom?" Obito scoffed. "Who do you think you're fooling, kid? Who is your mom—does she run the hospital or something?"
"My mom is the instructor teaching this class. Her name is Higashino Megumi. And my name is Higashino Shin."
"…Uh." Obito finally hit a wall.
He couldn't say another word. Offending the instructor would mean risking Rin's chance to study—and whenever Rin was involved, Obito suddenly became very careful.
"Oh, so you're Megumi-sensei's child," Rin said, curiosity lighting her eyes as she studied Shin. "Now that you mention it, you really do resemble her."
"Yes, Senior. My name is Higashino Shin. I hope you'll guide me in the future."
"I'm Nohora Rin, and this is my companion, Uchiha Obito. It's nice to meet you."
"Likewise," Shin replied with a polite smile—and then raised an eyebrow at Obito. "Let's work hard together and become outstanding Medical Ninjas."
"..." Obito was already seething.
This brat dared to talk so casually with his Rin—and even provoked him on top of that. He really wanted to beat him up.
Of course, he wouldn't actually hit a child. Before his fall into darkness, Obito was genuinely kind-hearted and warm.
It's just his personality and character are… painfully awkward.