Uchiha Gate: From Konoha to One Piece

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"Hm? Nawaki, what did you just say? Say it again!"

Tsunade's brows shot up in a scowl as she glared at Nawaki, her tone carrying a clear threat.

How dare he talk like that about his elder sister? Did he want to rebel?

"Hahaha!"

Nawaki instantly froze, his nerves kicking in. He let out an awkward laugh, frantically waving his hands.

"Nothing! Nothing at all! What I meant was, Sis, you're the greatest! Jiraiya should count himself lucky to have someone as amazing as you as his teammate. It's like he's been blessed by eight generations of good karma!"

"If it weren't for you keeping him on the straight and narrow, who knows where he'd have ended up? He might not have even survived as a wandering sage."

"You're practically a saint!"

Finishing his flattery, Nawaki shot Tsunade a thumbs-up with a face full of admiration.

The others—Kaito, Uzumaki Mito, and even the First Hokage—held back their laughter, clearly amused.

Tsunade, however, seemed pleased, nodding in approval. "Not bad. I like hearing that. Consider yourself spared!"

"I'm heading off to find Orochimaru now. The sooner I confirm this, the sooner I can put my mind at ease. Later!" With that, Kaito stood up, said his goodbyes to the others, and disappeared with a teleportation jutsu.

— — — 

The next moment, he appeared directly in the Research Department, inside the lab where Orochimaru and Tobirama were working.

"Hm?" 

Both Tobirama and Orochimaru glanced up, slightly startled by his sudden appearance, before returning their attention to their work.

Tobirama spoke first, "What brings the Fourth Hokage to the lab today?"

"Indeed," Orochimaru added with a sly smile, turning toward Kaito. "I assume it's something important?"

"It is," Kaito confirmed, retrieving two vials containing blood and cellular samples. He handed them to Orochimaru. "I need your help analyzing these samples. Specifically, I want to check for any signs of external genetic pollution."

"Oh?"

Orochimaru paused, his interest piqued. He set down his current project and arched an eyebrow. "Genetic pollution? That's quite an intriguing topic."

"I see you're quite focused on genetic purity, Kaito," Orochimaru continued, his curiosity growing. "Running a test is no problem at all."

"Ever since I got those foundational texts on genetics from you, I've been engrossed in the subject. After countless hours of study, I've gained some solid insights. Running this analysis should be easy."

"By the way, whose blood and cells are these?" he asked, taking the vials and glancing at Kaito.

"Jiraiya's," Kaito replied bluntly.

"What?!"

Orochimaru's pupils shrank in shock. "How could Jiraiya's cells show signs of genetic pollution?"

He knew Kaito wasn't one to speak lightly about such matters.

Immediately, Orochimaru's mind raced, trying to piece things together.

Suddenly, his eyes gleamed with realization, and he narrowed them at Kaito. His tone turned serious.

"Could it be related to his training in Sage Mode?"

"Does this mean there's a significant flaw in the Sage techniques of Mount Myoboku?"

"Oh?"

Tobirama, who had been quietly working nearby, also stopped what he was doing and turned toward them, clearly intrigued.

He'd heard something extraordinary. Sage Mode wasn't unfamiliar to him.

Back when his elder brother mastered Sage Mode and displayed its overwhelming power, Tobirama—a master of forbidden techniques—was deeply tempted to study and learn it himself.

But he ultimately failed.

Hashirama's method of learning Sage Mode relied entirely on innate talent, with no real technique involved. It was inaccessible to others.

Later, Tobirama managed to obtain a summoning contract scroll from Shikkotsu Forest, one of the Three Great Sage Regions. However, before he could research it, his brother passed away, and the First Great Ninja War erupted. He never got the chance to delve into Sage Mode.

Recently, he'd seen Mount Myoboku's toads apologizing to Kaito and even offering their Sage Mode training methods. Tobirama had reviewed those methods and had been tempted to try them out himself, even in his undead state.

But now, you're telling me Mount Myoboku's Sage techniques might have significant issues?

Having read the same genetic research books Kaito provided, Tobirama had a clear understanding of genetic pollution—and it wasn't something to take lightly.

Still, for someone like Tobirama, who wasn't aware of Kaito's advanced chakra refinement techniques, the impact of potential pollution from Sage Mode seemed limited.

As long as one didn't maintain Sage Mode continuously, but only used it in battle, the side effects might never become a real issue in their lifetime.

"You're as sharp as ever," Kaito said with a faint smile, acknowledging Orochimaru's quick deduction. "Last night, I attempted to train in Mount Myoboku's Sage Mode..."

Kaito then shared the key points of his training experience and subsequent findings with Orochimaru.

Because Tobirama was present, he carefully omitted certain classified details, such as the Primal and Sage chakra refinement techniques.

Instead, he focused on the issues he'd discovered with Sage Mode.

"My research has revealed that the Sage training methods of Mount Myoboku—and possibly the other two Sage Regions—introduce external energy into the user, which gradually erodes and mutates their genes over time."

"If one trains extensively in Sage Mode, and especially if they replace their chakra with Sage Chakra over the long term, this process accelerates drastically."

"What consequences do you think this will bring? You should be very clear about that."

Kaito fixed his piercing gaze on Orochimaru as he spoke.

"Hiss! This really is a serious problem, isn't it?" Orochimaru immediately caught on to the underlying message in Kaito's words.

He was also someone bound by a contract and had practiced the technique of refining that Primal Pure chakra.

Naturally, he understood that due to this technique, all contract holders were fundamentally different from non-contracted ninjas.

These individuals could continually accumulate chakra and enhance its quality through the process of refining Primal chakra.

Similarly, when a contracted ninja practiced Sage Mode using the Primal chakra method, their regular chakra would inevitably be replaced by sage chakra.

This sage chakra would be stored the same as the Primal Chakra accumulating over time.

But this had its side effects. Sage chakra would influence their bodies at all times, accelerating genetic mutations at an astonishing rate.

It could speed up the process of transforming a ninja's genetic makeup to resemble the animals of the Three Great Sage Regions—snails, toads, or snakes—by thousands of times.

What might have taken decades or even centuries to erode someone's body could now occur in just a few years—or even sooner.

At that point, contracted ninjas practicing the Sage Arts of the Three Sage Regions might all end up turning into slugs, toads, or snakes.

The mere thought of such a scenario made Orochimaru shudder.

Although he had injected himself with snake DNA to enhance his power and align with his snake-based jutsu, he had never truly intended to become a snake.

A snake without hands or feet wouldn't exactly be ideal for conducting experiments.

Furthermore, over the years, he'd noticed that the snake DNA in his body had begun to distort his senses and rationality, increasingly aligning his personality and aura with that of a snake.

This was far from a good sign.

Especially now that he no longer intends to pursue immortality through body-hopping techniques. This influence had become an even greater concern.

Thanks to the many techniques taught to him by Kaito, he no longer needed the body-swapping technique to extend his lifespan.

After studying genetics, he had come to realize that the drawbacks of snake DNA outweighed its benefits. He now wanted to remove the snake DNA from his body.

But before he could act on this, Kaito had shown up with Jiraiya's blood sample and the issue of sage mode.

This made him acutely aware of how reckless and foolish he had been to tamper with his genes so casually in the past.

"So, Kaito, if Jiraiya's genes really are corrupted, do you have a way to solve this?" Orochimaru asked, looking at Kaito with hopeful eyes.

"Pfft!"

Kaito chuckled, scrutinizing Orochimaru with a playful expression. "You're actually asking if I can fix your snake DNA problem, aren't you?"

"Heh heh!" Orochimaru let out an awkward laugh. "I knew I couldn't hide anything from you, Kaito."

"Yes, back then, to develop snake-compatible jutsu, I injected myself with snake DNA.

"At the time, I didn't understand genetics well enough to realize the risks.

"Looking back now, I was way too reckless. I'm counting on you, Kaito, to help me."

He felt that his own problem might be worse than Jiraiya's.

After all, Jiraiya hadn't shown any signs of his personality or habits shifting toward that of a toad—yet.

What's that? You think Jiraiya's perversion might be related to toads?

Well… that's a bit of a stretch.

You can't assume toads are perverts just because of that whole "toads wanting to eat swan meat" story!

In Orochimaru's view, Jiraiya's lecherous nature was something he was born with.

"Your snake DNA issue does seem more severe," Kaito said.

"I'll need to analyze your genetic pollution before I can say for sure.

"But don't worry. As long as you don't practice Sage Mode before addressing your genetic problem, you should have plenty of time.

"I'll definitely find a solution."

Kaito shook his head and reassured him.

"Whew, that's a relief!" Orochimaru sighed, though he still didn't get a definitive answer.

As a contracted ninja, he knew Kaito's true brilliance lay in his unparalleled genius.

If Kaito said he'd find a solution, then he surely would.

"What kind of cryptic conversation are you two having?"

"I can tell there are secrets between you—and even between you, Tsunade, and my sister-in-law—that you're deliberately keeping from me, my brother, and Madara."

"Mind telling me what that's about?"

"Don't tell me it's because we're just reanimated corpses?"

Senju Tobirama wasn't an idiot. He had picked up on the gaps in Orochimaru and Kaito's conversation earlier.

Their words seemed normal on the surface but were clearly missing key details.

It was obvious they didn't want him to know something, yet Orochimaru understood it instantly.

That was frustrating.

Here he was, working hard, only to be kept in the dark like some expendable grunt.

"Figures. The Uchiha Clan never produces anything good!"

Tobirama glared at Kaito with open disdain. Whatever goodwill he had just started to develop toward Kaito vanished in an instant.

Kaito sighed. "I'm not deliberately keeping secrets from you, nor is it because you're a reanimated corpse.

"These are core secrets of mine, and unless someone meets certain conditions and forms a special contract with me, I won't reveal them to anyone."

"This isn't about targeting you specifically."

"In fact, just before coming here, I made such a contract with the First Hokage since he met the conditions. I've shared these secrets with him."

"So, Tobirama, you don't need to feel like I'm unfairly favoring anyone."

"The truth is, among you three reanimated corpses, only you and Madara haven't met the requirements for a contract yet. That's the only reason you're out of the loop."

"If it were up to me, I'd really like for both you and Madara to qualify and form a contract with me."

"It would benefit both of you and me greatly."

"Unfortunately, I know that's not realistic."

"You and Madara don't have much goodwill toward me, so it's unlikely either of you will ever meet the requirements, at least in the short term—or maybe ever."

"Such a pity…"

Kaito finished with a regretful shake of his head.

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