Hiruzen Sarutobi listened to Hiruko's report without so much as blinking.
When Hiruko said "cellular fusion," he wasn't talking about a vague buzzword. His core idea was blunt and dangerous in the way real research always was: introduce foreign cells into a human body, push the system hard enough, and the body might produce foreign Chakra. If that happened, it could trigger abilities that person never had before.
It wasn't far from Konoha's old line of thinking, the one that had driven people to inject Hashirama Cells in the hope of awakening Wood Style.
The difference was that Hiruko, at least for now, was careful.
He wasn't starting with the most aggressive material. He was working his way up from lower-risk samples, and he had case after case, methods and conditions that had actually produced stable fusion.
None of them involved a Kekkei Genkai. Not yet. Lack of material alone made that a wall he couldn't climb.
But he'd still pulled real conclusions from it, especially about compatibility.
Compatibility. Integration. That kind of language hooked Hiruzen immediately.
Because Tobirama Senju's notebook held one detail that had always rubbed wrong, even by Tobirama's own strict standards. A note that read less like logic and more like a grim joke from fate.
Why were his cells and Izuna Uchiha's cells so compatible?
Hiruzen didn't need long to connect it.
Hiruko's technique might be exactly what the hidden experimental body needed.
If a body built on Izuna Uchiha's foundation could be made to truly accept Tobirama's cells, not as an infection, not as a patch, but as something seamless, something that became one whole, then the "defects" Tobirama had hit might finally be solved.
As he spoke, Hiruko kept stealing glances at the Hokage's face.
And the more he watched, the more unsettled he became.
He's listening way too seriously.
Hiruzen looked like he was planning a war, not hearing a research proposal.
But the deeper that focus went, the more warmth spread through Hiruko's chest.
Researchers didn't bleed their lives into a project just to have it waved away. He didn't want to be dismissed by anyone, even the Hokage.
And being taken seriously, really taken seriously, hit him in a place he didn't like admitting existed.
Even if he didn't understand a word, Hiruko thought, that attitude alone would be worth my respect.
So he stopped holding back.
He laid out everything, every thread of his reasoning, the paths he'd tried, the ones he thought could work if he had the right environment and the right support.
When he finally finished, he realized his throat was dry.
"That's the gist of it, Hokage-sama."
He couldn't help it, the satisfaction in his voice. Usually the only person he could talk to like this was Orochimaru.
Being able to speak freely for this long, in the Hokage's office of all places, and not be treated like an annoyance… it felt absurdly good.
"Hm." Hiruzen lifted his teacup, eyes still thoughtful. "Drink too. Give me a moment."
Hiruko smiled without meaning to and took a careful sip of the tea.
It was just tea.
But it wasn't about the tea. It was about sitting here, being seen, being acknowledged like his work mattered.
Then Hiruzen spoke again, and Hiruko froze halfway through his next sip.
"Your direction is solid."
"You mentioned external environmental stimulation during fusion. I considered something similar when I was younger."
"Even in cloning work, the gestational environment of the host body, and the way the soul and flesh interact, can influence how genes express."
"If we treat fusion, roughly, as a stage of cellular differentiation, then some approaches from cloning might be worth borrowing."
Hiruzen's voice stayed calm and steady as he unpacked the logic, sliding smoothly from one concept to another.
"Chakra is both the main mechanism and a potential source of interference. This line of research has real value, but it will demand repeated exploration, and that means manpower and resources."
He kept it at the level a leader should, talking systems, frameworks, standards. The kind of talk that sounded professional without getting lost in tiny technical weeds.
And even if someone pushed him into those weeds, he had Tobirama's notes behind him like a hidden spine.
The Second Hokage's legacy was… generous.
And Hiruzen had learned how to use it.
By the time he finished, Hiruko had set his cup down without realizing it. His eyes were wide.
Wait.
Third Hokage-sama, you actually understand this.
Not just the big picture, either. The details, the angles, the way he casually pointed out pitfalls like he'd personally tripped over them before.
For a terrifying second, Hiruko almost felt like he was talking to Orochimaru.
"Third Hokage-sama," he said, voice catching, "you… you've studied research too?"
Hiruzen gave a quiet laugh and shook his head. "When I was young, I was interested. After I became Hokage, I realized I'm only ordinary. I don't have the energy to handle the village and keep up real research."
He sighed, not bitter, just honest. "Research demands imagination, focus, and time. In the end, I have to rely on young people like you."
Hiruko's jaw tightened.
Ordinary?
If this was "ordinary," what did that make everyone else?
But the thought slid into something stranger, something that loosened the knot in his chest.
Maybe he wasn't some forgotten piece of scrap metal after all.
Maybe Konoha's upper levels were just full of people who'd been quietly terrifying this entire time, and he'd been measuring himself against monsters without realizing it.
Hiruzen set his empty cup down and looked at him with an easy smile.
"Your direction is good. Have you considered developing it with the village?"
"Konoha is going to invest heavily in jutsu development and technical research from here on."
Hiruko shot to his feet so fast his chair scraped. He grabbed the teapot and poured for Hiruzen, hands tense.
He even wrapped a thin layer of Chakra around his fingers without thinking, just to steady the motion.
Spilling tea for the Hokage would be humiliating beyond belief.
"Hokage-sama, if the village needs it, I'm willing to offer the jutsu to Konoha," he blurted, eager and a little too quick to please.
Hiruzen's eyes softened, but there was a hint of reproach in his tone.
"You, honestly…"
"Offer it to the village?" He shook his head. "I know how researchers think. This is your effort, your blood."
He leaned back slightly. "When I say develop together, I mean together. The village will support you with personnel and funding. Your name will be clearly listed as the developer. But the results will be shared by all of Konoha."
He tapped the teacup lightly. "And the social side of things. Researchers want to focus, speak through performance and results, not spend half their lives navigating favors and politics. Right?"
Hiruko stared.
He didn't even have a clean response ready.
You understand research, and you understand researchers.
Not the shallow kind of "I read a book once," either.
The real kind.
"You're… you're exactly right," Hiruko said, and his voice sounded different even to his own ears.
Hiruzen took another sip and kept that same friendly tone.
"The reforms, the jonin circle has heard about them by now, hasn't it?"
Hiruko nodded quickly.
"Good." Hiruzen's gaze sharpened, warm but firm. "Your talent doesn't lose to Orochimaru's. This reform is meant to find people like you."
He smiled like he was talking to a stubborn grandson. "I can't let you keep hiding anymore. I need you carrying more weight. Do you have the confidence?"
Something snapped into place in Hiruko's chest.
He stood straight like a spring released, back rigid, chin up.
"Yes, Hokage-sama. I will follow your orders!"
Hiruzen waved him down with a small laugh. "Sit, sit. We can talk properly."
They spoke for a while longer. When Hiruko finally left, he looked like he'd been lit from within, excitement practically leaking out of him.
He even offered, on his own, to organize his current results immediately and submit them to the village.
Hiruzen wasn't surprised.
He'd given him respect, status, and a clear road forward. Hiruko responding with loyalty was only natural.
When the office finally quieted again, Hiruzen rubbed his thumb slowly along the edge of the desk, thinking.
"Orochimaru," he murmured in his head, "how is your soul research coming along?"
He didn't call for him.
He would wait for Orochimaru to come and report on his own.
A small piece of understanding between teacher and student, and one more step in building trust that wouldn't crack when pressure came.
The next day.
An Anbu arrived with a letter in hand.
"Hokage-sama. This is a letter for you from Kushina Uzumaki."
Hiruzen's eyes narrowed slightly, interest stirring.