Inside the training room, Yuya Kudo stared at the brand-new scroll in front of her.
As the director of Konoha Hospital, she wasn’t particularly proficient in formula theory.
But she could still understand most of what had been written.
And that was exactly why the contents became more horrifying the further she read.
Perfectly integrated formulas.
Far more demanding requirements for Chakra Control.
A complete restructuring of the Healing Resuscitation Regeneration Technique.
By the time Yuya reached the end of the scroll, even her hands had begun trembling.
“So this is what a genius looks like…”
She slowly lowered the scroll.
For a while, she simply stared at the place where Koji had been sitting earlier.
She genuinely didn’t know what to say.
If they classified the technique purely by learning difficulty, then this modified version undoubtedly qualified as an S-rank medical ninjutsu.
There was only one problem.
No one could actually use it.
Perhaps Tsunade—one of the Legendary Sannin—might have been capable of performing it.
But where exactly were they supposed to find that legendary woman now?
Yuya closed the scroll.
“So you developed the technique yourself…”
“…but you can’t use it yourself?”
She suddenly felt exhausted.
For a shinobi, there were few things more painful than creating a technique that exceeded their own ability to perform.
Yuya was even beginning to worry that the failure might crush Koji’s confidence.
Or worse— push someone with his talent down the wrong path.
Still, the scroll wasn’t useless.
Far from it.
The portions designed to reduce chakra consumption could be incorporated into the original group version of the Healing Resuscitation Regeneration Technique.
The improved cellular differentiation process could also be adapted.
The problem was that even after those changes, the demands placed on the medical ninja remained extremely high.
Konoha Hospital couldn’t even gather four people capable of meeting those requirements right now.
Which meant both possibilities—
Koji’s solo version…
and a comprehensively improved cooperative version based on his research— currently existed only in theory.
Perhaps several years from now…
or several decades from now…
someone would finally be capable of performing them.
When that happened, Konoha’s medical system would advance once again.
But for the person who had created the technique…
perhaps that made the situation even crueler.
“Koji…”
Yuya looked through the window.
A lonely figure could still faintly be seen in the distance.
She couldn’t help feeling that there was something desolate about him.
Unfortunately— the Koji Yuya imagined and the actual Koji were two completely different people.
The moment he finished developing the solo Healing Resuscitation Regeneration Technique, Koji had already moved on to the next stage of his plan.
Half a month had passed since Danzo’s assassination attempt.
Just like the previous incidents, the mysterious Kumogakure infiltrator was already beginning to fade from public discussion.
During those same two weeks, Koji had quietly taken small amounts of nutrient solution and glass containers whenever he performed surgery.
Those supplies were meant to preserve the Sharingan embedded in Danzo’s stolen arm.
As for the arm itself—
Koji intended to convert nearly all of it into Hashirama stem cells.
He couldn’t supply enough chakra to complete the full Healing Resuscitation Regeneration Technique.
But if he only used the earlier portion responsible for cellular dedifferentiation?
That was much easier.
Once he successfully obtained Hashirama stem cells, he could begin conducting large numbers of experiments to determine how to reduce their side effects. Get faster updates on g.com.
That research could no longer be delayed.
The underground storage room beneath Koji’s small house wasn’t large.
Tonight, however, candlelight illuminated the entire space.
Under the flickering light, Koji placed a large container in front of him.
It was filled with pale-green nutrient solution.
Floating inside— was Danzo’s severed right arm.
The Sharingan embedded along its surface were motionless.
Even so, the sight was unsettling.
Though perhaps the most unsettling thing in the room wasn’t the arm.
It was Koji.
Under the candlelight, he calmly activated his Chakra Scalpel and began cutting out the Sharingan one by one— together with the optic nerves attached behind them.
Each eye was immediately placed into a separate glass container filled with nutrient solution.
The solution had been specially modified by Koji.
Compared with Konoha Hospital’s standard nutrient fluid, his mixture was better suited to maintaining the activity of Sharingan tissue.
The work continued until dawn.
Only then did Koji finally finish removing all of the eyes.
Excluding Shisui Uchiha’s Mangekyō Sharingan— there were eleven Sharingan in total.
Every single one was fully matured with three tomoe.
Koji stared at the collection.
These obviously couldn’t have been Danzo’s entire stockpile.
Danzo had already returned to Root by now.
There was even a good chance he’d already implanted another Sharingan into his right eye.
Replacing the arm would be much harder.
Unless Danzo cooperated with Orochimaru again, reconstructing something similar wouldn’t be simple.
Koji stored Shisui’s eye separately.
Despite his exhaustion, he immediately turned his attention toward Danzo’s arm.
After roughly ten minutes of experimentation, he established a rough conversion rate.
One finger— roughly one usable sample of Hashirama stem cells.
Now that he had a baseline, there was no reason to proceed slowly.
Koji activated his Chakra Scalpel.
He divided the remaining arm into eighty separate portions.
Then— he began repeating the same process.
Again.
And again.
And again.
Fortunately, the trait Koji had obtained after pushing Chakra Refinement through its Limit Breaks was Recovery.
Without that accelerated chakra recovery, completing this much work before nightfall would have been impossible.
By the time he finally stopped, almost the entire arm had been processed.
Koji sealed Shisui’s right eye and most of the Hashirama stem-cell samples into one scroll.
The remaining samples were stored separately in another.
Only then did he begin cleaning the storage room.
His cleanup this time was somewhat careless.
Koji wasn’t particularly worried.
When he’d left Konoha Hospital, he’d deliberately brought home several fish used as experimental subjects.
Even if someone later discovered traces of experimentation in the underground room— there was nothing that immediately connected them to Danzo.
Once everything had been handled, Koji finally collapsed onto his bed.
A full day and night of work.
And the results were worth it.
Naturally— the proficiency accumulated there.
A familiar panel appeared.
[Healing Resuscitation Regeneration Technique — Limit Break +1 (19%): Control +1]
Koji studied the new trait.
Control.
Its effect primarily applied during the secondary differentiation of stem cells.
Useful.
Although not exactly what he’d wanted.
The trait Koji had hoped for most was something that would reduce the technique’s chakra consumption.
Unfortunately…
that hadn’t appeared.
Still, the Healing Resuscitation Regeneration Technique had room for further improvement.
And perhaps the next breakthrough wouldn’t come from altering the formula itself.
Maybe the real answer lay in changing the type of chakra being used.
What if, instead of converting ordinary Mystical Palm chakra…
he used Yang-nature chakra as the foundation?
That might produce a completely different result.
There was only one problem.
Yang-nature chakra was troublesome.
Koji certainly possessed it.
Every living being did.
At its essence, Yang Release was closely tied to life energy.
But possessing something and being able to actively use it were very different matters.
Right now—
Koji had it.
But couldn’t bring it out.
Which effectively meant he didn’t have it at all.
Koji closed his eyes.
For now…
he needed sleep.
At the same time, Konoha Hospital remained brightly lit despite the late hour.
Today had been miserable.
Because Koji hadn’t shown up at all— the rest of the hospital staff had practically worked themselves into the ground.
Yet none of them were complaining now.
Every medical ninja present was staring solemnly at the scroll placed in the center of the training room.
“This…”
One of the medical ninja capable of participating in the original Healing Resuscitation Regeneration Technique swallowed hard.
“This is what Koji produced in half a month?”
Other people might not understand every detail.
But those already familiar with the original technique understood exactly what they were looking at.
“Yes.”
Yuya’s voice was calm.
“Half a month.”
Her gaze settled on the scroll.
“What he accomplished here might take us decades to reproduce.”
The room fell silent.
Several medical ninja slowly lowered their heads.
Earlier, some of them had been annoyed that Koji had taken the entire day off while everyone else drowned in work.
Now?
Nobody said a word.
Half a month of research— equal to decades of progress.
So what if he rested for a few days?