Ruri went to the Hokage Building and didn't spend much time before returning home.
When she came back, Hakushi saw that Ruri was holding a scroll, which she casually tossed to him.
"Thanks."
Hakushi didn't make a fuss and caught the scroll directly.
"Just hurry up and finish your Immortal Technique research."
"This kind of thing really is a bit difficult. After all, information on Immortal Technique is too scarce. It would even help to have references—if I could study the Sage Art Systems of the Three Great Sacred Lands, it would no doubt be a huge help to my work."
"Give it up. Unless you've signed a summoning contract with one of the Three Great Sacred Lands, it's nearly impossible to find them, let alone gain Immortal Techniques from them."
"So, the Sannin really are extraordinarily privileged ninja, huh."
The rumors about the Konoha Sannin having close ties to the Three Great Sacred Lands were nothing new by now.
Not only were they Hokage Disciples, but also backed by the Three Great Sacred Lands. For ordinary ninja, that was something they could never hope to achieve, even in a lifetime.
"But even the Sannin—no one ever heard about them truly mastering Immortal Techniques."
"Of course. I don't know if the Immortal Techniques trained by summoning beasts are the same as the ones I'm researching, but fusing natural energy with ordinary chakra does indeed carry considerable risks; you might even lose your life if you're not careful."
Hakushi sat down in the room, took a soft sip of his tea, then unfolded the scroll in his hand.
The scroll began with the name of the ninja technique and its developer.
Spirit Transformation Jutsu.
Developer: Previous Hokage, Senju Tobirama.
According to the notes, Spirit Transformation Jutsu is a technique that lets the soul leave the body and travel anywhere, regardless of distance, even killing enemies directly.
But after the soul leaves the body, the spiritual body still retains the caster's consciousness, so this ninja technique can be applied in many ways, not just combat—transmitting information, large-scale sensory perception, even passing chakra to comrades; Spirit Transformation Jutsu can do all this.
Have to admit, the Previous Hokage, Lord Senju Tobirama, who developed this technique, is a figure to be respected.
He was said to have fallen on the battlefield in the First Ninja Realm World War—what a pity.
Hakushi very much agreed with many of the Previous Hokage's ideas.
Building the Ninja School, establishing the Anbu, dividing and suppressing the Ninja Clans, raising the status of commoners, creating the various secret techniques and ninja techniques belonging to Konoha Style… His influence is visible in politics, science, and the military, and he was the originator; all Ninja Villages in every country have followed his example.
The era of one nation one village was created by the Senju Clan and Uchiha Clan, but in reality, this system was only nominal and empty inside. If not for the Previous Hokage, Senju Tobirama, so-called Ninja Villages… thinking carefully, weren't really different in substance from the Warring States Era, with Ninja Clans occupying their own territories in constant war.
It wasn't until the Previous Hokage took office and pushed a series of epoch-making reforms that this deformed Ninja Clan rule over the village gradually turned into something better, using the commoner class to restrain the shinobi class. From then on, Konoha's various sides formed a stable balance, checking and depending on one another.
The methods of maintaining balance are awe-inspiring.
The only pity is that there was no follow-up.
With the outbreak of the First Ninja Realm World War and the death of the Previous Hokage, Senju Tobirama, even though he still had ambitions left unfulfilled, they could only drift away with the wind, leaving the village's future to the current Third Hokage.
As for the Third Hokage, Hakushi didn't know much, possibly because the brilliance of the Previous Hokage outshone him, so many people simply overlook this Third Hokage's achievements.
After all, most systems were already perfected during the Previous Hokage's era. Later generations, no matter what they did, couldn't surpass the previous era, so all that's left is to see if the Third Hokage can do something extraordinary.
After thinking all this, Hakushi took the Spirit Transformation Jutsu scroll and headed back to the underground laboratory.
He had already injected natural energy into the experimental subject's body, and needed some time to observe and collect data.
Now, it was time to consider the "Caged Bird" Curse Seal problem.
Regarding the Caged Bird, Hakushi had already researched for a period, but due to missing data and still-incomplete analysis of the deeper structure of chakra, progress had stalled for a long time.
According to Ayane, once the Caged Bird is inscribed, it lasts a lifetime, only disappearing at the moment of death.
In other words, the Caged Bird can be removed under the condition of "death."
So then, what kind of "death" would that be?
Is it the body or the soul?
What kind of properties does chakra exhibit in all this?
Humans are born producing chakra; if they lose chakra, they die.
So if Ayane were brought to the brink of death by exhausting her chakra, would the Caged Bird be removed?
Of course, this "death" wouldn't be real death, but a kind of pseudo-death, like dying but not quite.
Afterward, if chakra was replenished in Ayane, she could awaken from the pseudo-death state.
The prerequisite for this experiment is to verify one assumption first.
That is, after a person loses all chakra—will they really die?
If losing all chakra doesn't necessarily mean death, then—where does chakra come from?
Why is it a necessary life energy for human survival?
Is death by loss of chakra a physical death, or a death of the soul?
Is it possible to make a human enter a very peculiar pseudo-death state after losing all chakra, and then, by replenishing chakra, revive them? Can something like this really work?
If all of these can be verified through experiments, then removing the Caged Bird might no longer be a difficult problem.
And it would answer many of Hakushi's doubts.
Hakushi recorded all of these conjectures carefully in his notebook that he carried with him.
That's science: first have questions, then make guesses, and only after that try to prove or disprove them.
Therefore, research on Soul Jutsu is absolutely necessary.
The only troublesome thing is, it's wartime now, and he might be sent out on missions at any time, which means there's not always time to experiment here.
◎
Listening to the eerie cries coming from the experimental subject on the operating table—so painful he couldn't bear it, wanting to scream but unable to make a sound, only able to hear the faint struggling noises as his throat felt like it would burst—
Hakushi calmly watched the test subject writhing and twitching in agony on the operating table, his face twisted in pain. Unmoved, with practiced hands, Hakushi sliced off a patch of skin on his arm that had been eroded by natural energy. The skin was a vague green, which he placed in a dish and examined under a microscope.
Next, he looked to the data screen on the computer, showing real-time heart rates from the subject on the table, and the fluctuations after natural energy and chakra fused together.
From uncooperative subjects at first, these test objects had turned into broken, emotionless puppets, lacking even fear in their eyes.
Hakushi had to admit, this was a bit of a miscalculation.
He hadn't expected the fusion of natural energy and chakra inside the human body to inflict such terrifying spiritual and physical trauma to the recipient.
So, whenever a test subject showed signs of mental collapse, he would halt the experiment and administer sedatives, then bring in a new subject.
By rotating like this, sustainable use was possible—it was a way to save resources.
Glancing at the few shivering figures pressed against the wall, Hakushi shook his head; seriously, these guys really didn't have any spirit of sacrifice for science.
If his experiment succeeded, they could go from ordinary people to bodies full of Sage Art chakra. Even if they still couldn't use ninja techniques, their life force, strength, speed, and reflexes would all change dramatically.
Not to mention, longevity past a century shouldn't be a problem.
As for immortality… Hakushi let out a helpless sigh; he realized the more he thought, the more absurd his ideas got.
"The natural energy research is pretty much at its initial conclusion. I still need to further extrapolate the Sage Art chakra data to raise the fusion success rate, but next I can focus on resolving the Caged Bird Curse Seal…"
Hmm? Wait!
Hakushi suddenly noticed an extremely serious problem—how was he supposed to collect detailed body data on Ayane's current state?
Right now, he was living in the Uchiha Clan Land, and Ayane was from the Hyuga Clan.
If he brought Ayane here, and Ruri happened to discover her…
A slight cold sweat appeared unnaturally on Hakushi's face.
He needed to quickly calculate: what were the odds he'd survive if discovered?