A hundred meters beneath Hokage Rock.
Hiruzen Sarutobi had used Earth Release to slip down here, opened layer upon layer of seals, and entered a long, narrow underground chamber.
A faint scent of decay hung in the air, while the walls and ceiling were made of dark stone hardened by Earth Release.
Rust-covered experimental tables and cultivation tanks lined the walls, containing all manner of "materials."
The cultivation tank at the far end was particularly eye-catching. Dense Sealing Jutsu covered its surface, and a thick transparent tube extended from its base into another container.
This was Senju Tobirama's Secret Archive.
He had visited this place long ago.
But Senju Tobirama's research ideas had been truly shocking...
After merely skimming through them, he had realized he could neither handle nor continue the work. After reinforcing the seals and taking the notes, he had sealed most of the equipment deep underground.
Hiruzen Sarutobi had long been extremely interested in it.
It was just that when he had first arrived in the Shinobi World, this could not be his top priority.
Once he had a little room to spare, Lord Hokage had hurried over in great excitement.
Remembering how, twenty years ago, he had nearly been injured by an explosion because he had not understood Senju Tobirama's Defense Array on his first visit, he could not help but smile.
Holding the Second's research notes, Hiruzen Sarutobi carefully examined these astonishing half-finished products one by one.
"This pile of black stuff must be that monster capable of absorbing the negative energy in people's hearts, right? What a shame it has no life left..."
Hiruzen Sarutobi marveled at Senju Tobirama's creativity.
The Second Hokage had once proposed an idea: using the negative energy that would always arise in people's hearts to create a monster that sustained itself on it, an artificial Tailed Beast.
The Second Hokage had called it "Zero-Tails."
"There are even a few Sharingan here? One-Tomoe, and a pair of Three-Tomoe..." These had most likely been spoils seized during the Warring States Period.
Still, there were fewer of them than Hiruzen Sarutobi had expected.
After all, Senju Tobirama's notes contained an extraordinarily detailed study of the Sharingan.
Its origins, structure, specific operating mechanisms, and even the methodology for awakening it had all been laid out.
If he could bring over a Three-Tomoe from the Uchiha Clan Compound and let him debate the Sharingan with Senju Tobirama...
Hiruzen Sarutobi believed his teacher would leave the other side utterly convinced.
His teacher must have had a Mangekyō Sharingan in a past life. Otherwise, how could he understand it this well?
All he could say was—
No one understood the Uchiha better than Senju Tobirama!
Walking up to the cultivation tank that resembled a Black Coffin, Hiruzen Sarutobi looked up at it.
He could vaguely guess a few things.
Based on the research notes, Hiruzen Sarutobi's past memories, and a little speculation.
Before the First Shinobi World War, Senju Tobirama had already been considering how to use Bioengineering to strengthen Konoha...
The first thing he had thought of was injured shinobi.
Shinobi needed to form hand seals. Helping those with damaged limbs restore their bodies was, both in intent and purpose, a righteous undertaking that fit the Will of Fire perfectly...
But as things gradually developed, Senju Tobirama had begun pondering how to clone an entire person.
Hiruzen Sarutobi could understand that as well...
Not even counting figures on the level of Senju Hashirama and Senju Tobirama...
Even the body of an elite Jonin would possess considerable combat power, even if it were used as a puppet or something similar.
But clearly, Senju Tobirama had failed.
According to his research results, for a shinobi with Chakra to develop from cells into a human body, a genome alone was far from enough.
The more talented the shinobi's cells were, the more likely attempts to clone them would result in a pile of chaotic, useless tissue.
Senju Tobirama had guessed that this phenomenon might be greatly related to the "maternal growth environment" and "nourishment of the soul," and he had listed quite a number of interfering factors as well...
With Hiruzen Sarutobi's current knowledge, both he and Senju Tobirama believed that unless the subject's body possessed some special trait, shinobi cloning would be difficult to replicate on a large scale.
They could only make tiny adjustments step by step, conducting endless experiments and relying on sheer repetition to happen upon the correct result.
Perhaps once the technology developed further, this problem could be solved.
After undoing the outer seals of the Black Coffin, what came into his view—
Was the body of a youth who looked both familiar and unfamiliar, around fourteen or fifteen years old.
He had a head of messy black hair and handsome features. His brows and eyes somewhat resembled Senju Tobirama's, yet were not entirely the same.
"Heh heh, Teacher..."
Alone in the laboratory, the usually composed Hokage's lips twitched involuntarily. "I've never met him, but the target of this Cell Fusion must be that person you kept mentioning in your notes, right?"
His name was Izuna Uchiha!
Hiruzen Sarutobi turned his head toward the other container connected to the tank.
Inside it were masses of cells resembling wood. With a slight sense, he knew they belonged to Senju Hashirama.
"Was the water soaked with Hashirama Cells filtered through Sealing Jutsu, then circulated to nourish this body?"
It was hard to say whether ordinary people had the habit of keeping diaries.
But researchers definitely had the habit of taking notes.
Senju Tobirama, who had stayed behind to cover the retreat on the battlefield and had not had time to erase his "life browsing history," had allowed Hiruzen Sarutobi, his inheritor, to see it all.
And he had read it with great relish!
Upon seeing this experimental subject, Hiruzen Sarutobi's imagination ran wild. He suddenly connected a few scattered lines from the notes and pieced together a little story.
One day, Senju Tobirama had pierced an enemy's chest with a Flying Thunder God Slash and torn off a piece of flesh in the process.
He had preserved it and begun cultivating it.
After becoming Hokage and gaining access to resources, he had, driven by some strange motivation during an experiment, tried cultivating the cells of his sworn enemy.
He had then discovered that after adding his own cells, the experiments that had always ended in complete failure finally showed a turning point.
After who knew how many minute adjustments and revisions, he had actually produced a fully formed human body!
He had fixed it inside the cultivation tank with layers of Sealing Jutsu.
He had planned to continue researching it once he returned from the battlefield...
Only...
Hiruzen Sarutobi stared at the body's joints and found what seemed to be defects, knots like those that appeared in someone whose Chakra pathways had been severed.
Having read the notes so thoroughly that he nearly knew them by heart, he immediately thought of the obstacle involved.
"What can make the auxiliary Chakra pathways conduct smoothly?"
"Lady Mito might know, but if I ask her, she'll notice what I'm thinking."
"What a bother. Brother repeatedly told her to keep an eye on my research."
The notes actually contained none of that. There were only rough scribbles reading "pathway conduction" and Mito's name crossed out.
Yet Hiruzen Sarutobi's gaze seemed to pierce through time and space, seeing Senju Tobirama's thoughts from back then...
Whether it was true or not, he would reason it out this way first!
The dead could not refute him for the moment, anyway...
Hiruzen Sarutobi's teeth ached.
What Senju Tobirama had done to Izuna Uchiha could not be described by "an undying feud" alone.
If one of them had been the opposite sex, it could have topped the rankings of some angsty tragic-romance novel.
He truly could not understand the affairs between the Senju and the Uchiha...
"I was still thinking about the body. Now that there's a ready-made one, it certainly saves trouble. It just needs a little refinement."
"Teacher, you didn't dare ask Lady Mito, so I'll ask her for you!"
Konoha's Hokage slowly closed the seals on the tank.
Without him, this research might have remained buried beneath Konoha forever.
As time passed, it might have collapsed, or perhaps some Hokage would have completely erased it as a forbidden part of history.
But things were different now.
Konoha had to start accelerating!
Thank you to all my readers for your continued support with your reading, monthly tickets, and favorites!
It's Monday today! Readers with monthly tickets, please give Xiaofan a couple!
Before you continue