The room Ieyasu stepped into was sterile, dimly lit, and heavy with antiseptic. The faint hum of chakra-powered equipment filled the underground lab with an eerie calm. Masked figures in white coats moved with quiet precision. Their masks bore no insignia—only slits for the eyes.
Hiruzen led him forward.
They stopped at a sealed operating chamber.
"Subject Six," one of the masked med-nin said. "Vitals stable. Chakra network activity: higher than average. No ailments or hidden injuries detected."
"Good. Prep him."
Ieyasu raised an eyebrow. "Prep me how, exactly?"
The lead medic turned. "We're about to place the Hashirama cells into a sealed graft. We'll monitor how your body reacts. If you reject it, the cells will turn hyperactive and basically devour you from the inside out."
"Hashirama cells," Ieyasu echoed, feigning surprise. "Fine. Go ahead."
Hiruzen gave a long, unreadable look. "You're certain?"
"Already told you, nothing's taking me down. Also, you're the one telling Tsunade about me assimilating her grandpa."
Hiruzen's brows twitched at that, but he couldn't really complain.
With a short nod, Ieyasu was strapped to the monitoring device.
The air chilled as a black container was opened. Inside was a sickly green gel with threads of blood and tissue swirling within.
"This was taken from the last viable specimen. Don't move."
Ieyasu smirked.
The procedure was short and brutal. The graft was applied to his shoulder; sealing formulae flared to life, anchoring the tissue to his body. Pain tore through him like a tide of fire and thorns.
He screamed. He writhed. But he endured.
For ten minutes, he gritted his teeth and focused his will like a blade. His chakra surged wildly, then settled. The seal markings glowed… then dimmed.
Silence.
"…The cells have stabilized at the expected activity level for a successful infusion," the medic said at last. "No further rejection. Chakra flow is… adapting. Rapidly. This is completely abnormal—even successful attempts shouldn't integrate this fast."
"What did I tell you?" Ieyasu panted, drenched in sweat. "I'm too damn sturdy. Now get me out of this spooky lab."
---
Two days later, he was back at the training ground like nothing happened.
Tsunade blinked. "Wait, didn't sensei say you were half-dead yesterday?"
"Hehe, did you miss me, Tsuna-chan?" Ieyasu grinned. "Wait, stop! Aaah!"
She battered him harder than usual.
"Should we be worried?" Jiraiya asked.
"Very," Orochimaru muttered, intrigued. "Can I inspect you?"
"No, you creepy snake," Ieyasu snapped, alarm bells ringing in his brain.
Hiruzen arrived, tossing a scroll to each of them. "Congratulations, you're now official genin. These contain chakra control drills, body conditioning routines, and a chakra paper to determine your strongest affinity. You'll report here every morning. First: determine your elemental affinity."
He glanced at Ieyasu. "You're exempt from today's conditioning. Monitor your body. Any sign of instability, report immediately."
"Understood." Ieyasu took the chakra paper, eager.
Jiraiya's was Fire. Orochimaru and Tsunade both got Earth.
Ieyasu's affinity was Wind.
'Not bad. Wind is useful and Vacuum-style jutsu are deadly.'
---
Training began in earnest.
Tsunade and Ieyasu sparred daily. She was stronger. He was faster. And now, with regenerative cells, he could take hits that used to hospitalize him. Each broken bone only made him laugh—much to Tsunade's puzzlement.
Jiraiya started clumsy, but improved quickly—solid with Fire & Earth Release and good at ambushes. His perversion was at an all-time low thanks to Ieyasu's ever-present threats.
Orochimaru was the quiet terror of the team—methodical, precise, and increasingly dangerous. He refined a snake-based taijutsu style full of deceptive feints and whiplash movements.
Hiruzen drilled them in teams, pairs, and solo. Tree climbing. Obstacle courses. Chakra shaping. Hand seal speed.
Ieyasu stood out unexpectedly in tasks, often using clever, unorthodox tactics.
By the end of the first week, all four could spar for an hour without collapsing. Ieyasu's stamina rose the fastest. He began sensing something from the cells inside him—slow, rhythmic pulses. Like a second heartbeat. And Hizakura began glowing faintly during intense exertion.
---
One evening, Hiruzen called him aside.
"The graft's stabilized far faster than expected. The medics say your chakra's already fully integrated."
Ieyasu looked down. The seal marks were gone.
"Does that mean it's weaker?"
"No. It means it's you now. You'll likely develop Wood Release traits—maybe not the full jutsu yet, but you'll see your recovery, chakra, and life force increase significantly."
Ieyasu nodded. "So what do I focus on?"
"Survivability and control," Hiruzen said. "The cells can mutate if unbalanced. Your own will is the safeguard. Stay focused. Don't let the power consume you."
"Got it."
---
The next day, Hiruzen summoned a creature for a test: a tiger the size of a van, courtesy of Enma the Monkey King.
Tsunade opened with a brute-force punch that staggered it. Jiraiya peppered it with ninja tools and fire tags. Orochimaru shaped the terrain to box it in. But it was Ieyasu who ended it—his Hizakura flashed, glowing with power, and pierced through the beast's spine.
The blade hummed afterward.
And in the silence, a whisper echoed in his mind—praise. A voice. A presence. The spirit was awakening.
That night, by the stream, he stared at his weapon reflecting the Moon's serene glow.
"Hashirama cells… legendary blade… teammates who hit like trucks… I'm on a roll."
The petals at the blade's edge shimmered as if smiling.
He smirked.
"Let's see how far we can go."
...
Over the next eighteen months, their progress only grew.
Tsunade discovered her passion for medical ninjutsu and advanced rapidly in her chakra control and Taijutsu. Orochimaru began hoarding knowledge of jutsu like a sponge. Jiraiya… did his best. Thanks to Ieyasu's advice, he even created Wild Lion's Mane with Tsunade's help.
Ieyasu pestered Hiruzen like a tick, recording everything his sensei showcased. He'd learned most of the non-classified techniques by now, but the A and S-ranks still needed real practice. Even with the Byaku-Sharingan, you had to be skilled enough to execute what you copied.
Still, he was confident.
Within a year, he'd be a mini-Professor.
In taijutsu, Tsunade still had him beat—butif he had Hizakura in hand, he could come out on top a lot of the time even in purely physical battles.
He didn't bully Orochimaru too hard—just enough.
You never poke a snake too much.
Even so, Orochimaru wasn't far behind him in learning rate. The guy was a freak.
Jiraiya was slightly behind them in progress, he would only shine once he found Moint Myoboku.
...
At the end of those 18 months, Hiruzen called them in.
"It's time. You'll be taking the Chūnin Exams."
Since only three could enter per team, they split into pairs:
Jiraiya and Orochimaru, Tsunade and Ieyasu.
Same as usual.
"I know you're all more than qualified," Hiruzen said. "But take it seriously. One last thing: the pair that performs best… gets a personal gift from me."
"Thank you, teacher!" Ieyasu bowed so low it was practically theft. 'Perfect. Flying Raijin, Uzumaki fuinjutsu—I'm coming for all of it, then all that's left will be secret or forbidden techniques I can affors to wait for.'
Tsunade punched his head without hesitation.
Orochimaru scoffed. "Fools always get ahead of themselves."
Jiraiya just said, "Don't underestimate the Great Jiraiya, Ieyasu!"
Nobody hit him anymore. They just moved on.
"I expect you all to uphold the name of the Hokage's students," Hiruzen said, sighing. "Disperse."
They'd rest the next day.
Hiruzen watched them go, rubbing his temple. 'They're monsters. Maybe I should've promoted them without the damn exam. I'm more worried for the other kids than I am for them.'