Souls were… weird.
"In my previous world, no one could prove souls even existed," Amamiya Kenichi wrote, brush moving smoothly across the paper in kanji. "There was that famous '21 grams' theory, but it was never really accepted."
In the modern world, people had argued endlessly about it.
Some said the missing 21 grams was the weight of the soul.
Others said it was just air, fluids, biological processes—nothing mystical, just chemistry.
"But here," Kenichi continued, "souls are real."
You could see them with the right jutsu.
You could drag them back from the Pure Land.
You could bind them to the living.
Souls existed.
The Pure Land existed.
Edo Tensei existed.
If you dropped this fact on his old world, it would flip the entire planet upside down.
Who didn't have regrets?
Who wouldn't want to see their dead family again?
If death wasn't the end but just… a change of address—
What would that do to religion, to crime, to war, to love?
Kenichi paused, then shook his head.
Those were questions for philosophers and politicians.
He was a scientist.
And right now, he cared about something much more specific.
"If a soul can control a body… can a body change a soul?"
His brush stopped for a moment.
Orochimaru's name appeared on the page.
Kenichi tapped the table thoughtfully.
If a person used Living Corpse Reincarnation to move into a different body—
And then lived in that body for a long time—
Would their soul start changing to match their new form?
Could a male soul, stuck in a female body, slowly become more "feminine" in instinct, habit, even thought?
Could behavior be reshaped from the outside in?
Orochimaru's future came to mind.
After he defected from Konoha in the original story, his personality became more and more extreme.
Colder. Sharper. Less human.
Was that purely psychological?
Or… was his soul being bent by the unnatural bodies he kept hijacking?
"If I could figure out how much the body influences the soul…"
Kenichi's eyes shone for a moment.
Then he imagined Orochimaru reading that line over his shoulder.
He immediately shivered.
Yeah. No.
If Sensei ever found out his disciple was planning a long-term "soul remodeling" project for him…
Kenichi could very easily end up as the one being "remodeled."
Into something cute.
And short.
And probably wearing a dress.
He calmly tore the sheet from his notebook, walked over to the small brazier in his room, and dropped it into the flames.
The kanji curled, darkened, and burned to ash.
Orochimaru was terrifyingly smart. If he ever picked up kanji out of curiosity and found those notes, Kenichi's "research proposal" would turn into his execution warrant.
Still…
The experiment itself?
He definitely wanted to try it someday.
Just… quietly.
And from a very, very safe distance.
The next morning, Kenichi attended Sarutobi Hiruzen's reinstatement ceremony.
"Yesterday he gets a new arm, and today he's back as Hokage already…" Kenichi clicked his tongue. "You really are in a hurry, old man."
Then again, it made sense.
Danzō was watching.
Orochimaru was watching.
The village had just lost its Fourth Hokage.
Right now, Hiruzen's prestige was at its peak.
If he didn't seize the moment and slam his old nameplate back onto the Hokage's desk, someone else might.
And the village needed stability.
Internally, to calm the grieving masses.
Externally, to scare other hidden villages out of trying anything stupid.
"Kenichi. Let's go. Today's tests aren't finished."
Orochimaru stood with his arms folded, eyes cold as he turned away the moment Hiruzen began another "Will of Fire" speech.
Kenichi didn't hesitate.
He'd heard that speech so many times he could probably recite it in his sleep. Backwards.
He followed his teacher out of the crowd and back to the lab.
In the Root-backed underground facility, Kenichi's expression grew serious.
He was… tired of this place.
Researching Hashirama cells.
Running rejection tests.
Logging failure after failure.
Slow, tedious, repetitive.
If it weren't for the funding—
If it weren't for the resources—
Orochimaru probably wouldn't bother, either.
And even here, in this "shared" lab, Kenichi knew there were experiments his teacher never let him touch.
Those had to be related to Living Corpse Reincarnation.
"Kenichi. I have a research assignment for you."
Orochimaru had changed into his lab coat and pulled on his gloves.
His voice was calm, but his eyes were serious.
Kenichi straightened instinctively.
"This project is simple," Orochimaru continued. "I want you to study how to stabilize and precisely control the proliferation of those cells."
Kenichi blinked once.
Then it clicked.
"Sensei… you mean—"
"Just focus on the research." Orochimaru cut him off, eyes narrowing faintly in anticipation. "If you succeed, it might become quite the… earth-shattering discovery."
Kenichi understood.
He knew exactly which cells Orochimaru meant.
Cancer cells.
Cells that broke the limits nature placed on normal cells.
Cells that devoured nutrients and divided endlessly.
Cells that showed no clear upper bound to their replication.
"Are they the key to evolution?" Kenichi had asked himself once.
Or maybe—
The key to immortality?
Right now, cancer killed the host before any "benefit" appeared.
The body collapsed long before the "infinite" cells finished their work.
But if you could somehow—
Stabilize them.
Control them.
Turn wild, destructive growth into structured, directed renewal…
That would change everything.
"Understood, Sensei," Kenichi said, eyes serious now.
This experiment wasn't difficult to start.
And he had a head start.
Over the past months, he'd found that cancer cells and Hashirama cells shared frighteningly similar traits.
In some ways, the First Hokage was like a walking, weaponized, perfectly-coordinated mass of "benign" cancer—
Every cell overflowing with life, endlessly regenerating, yet somehow balanced enough not to rip his body apart.
If you looked at it that way…
"Maybe Hashirama wasn't even human anymore," Kenichi thought, not for the first time. "Just a humanoid cluster of cheat-code cells in a human shape."
Cells that obeyed every rule that cancer cells broke—
and still refused to die.
But Hashirama did die.
No one knew exactly how.
Which meant even he hadn't truly escaped mortality.
For now, the "immortality" of Hashirama cells remained a theory, not a proven fact.
"Hope Sensei can leave Konoha soon," Kenichi muttered to himself later, alone in the lab as he organized his samples.
Too many eyes.
Too many rules.
Too many limits.
In the village, everything was constrained by politics, tradition, and reputation.
Outside?
It would be harder at first.
But with time, with resources, with the right allies…
His research could finally stretch its wings.
Orochimaru's new body plans.
Soul remodeling.
Stabilized cancer.
Immortality.
And maybe, just maybe—
He could guide his teacher, step by step, until Orochimaru completely adapted to his future identity.
Body first.
Then habits.
Then mind.
Then soul.
A long-term, full-package "gender and personality adjustment program"…
Kenichi smiled faintly.
"Project goal," he wrote in his mind. "Help Sensei gradually get used to his new self."
Just thinking about it made him a little excited.
And a little terrified.