Interlude

Seeing Jiraiya's haunted expression, the corner of Orochimaru's mouth twitched almost imperceptibly.

This guy was definitely thinking about something inappropriate again.

"Physiological monitoring."

Orochimaru couldn't be bothered to explain further. He pointed to a screen beside them, where a waveform flickered, then picked up several metal electrodes with wires attached.

"We'll record how your bodily functions change while you try to absorb and use Senjutsu Chakra.

That'll help us analyze and improve the training process..."

He did his best to explain in terms Jiraiya could understand.

"Oh, oh! So that's what this is!"

Jiraiya's wariness instantly turned into an awkward, silly grin as he realized what was going on.

"Man, I thought... Ahem, well, you should've said so sooner!"

He scratched his head, then began stripping with practiced ease.

His jacket and shirt came off in a few quick movements and were tossed aside, revealing a fairly well-built body.

Just as he reached for his waistband—

"That's enough. You don't need to take off your underwear."

Orochimaru finally spoke up to stop him.

Jiraiya froze mid-undressing, then laughed sheepishly and lowered his hands.

"Heh, I just figured we should get the most complete data possible."

He muttered something under his breath, then obediently stepped onto the slightly raised metal platform.

Orochimaru ignored his grumbling and clapped his hands.

"Poof!" "Poof!" "Poof!"

Several clouds of white smoke dissipated, revealing a number of Shadow Clones in the laboratory. Each headed for a different instrument and began making adjustments.

One Shadow Clone approached with electrodes and started attaching them to Jiraiya.

His chest, arms, even his forehead.

The cold touch made Jiraiya shiver.

"All set."

After confirming that all the equipment was connected properly, Orochimaru spoke to Jiraiya on the platform.

"Now try to absorb Natural Energy and gather Senjutsu Chakra.

Go by how you usually feel when training at Mount Myoboku. Don't force it."

First, he wanted to see how far Jiraiya had progressed, as well as learn some of the basic traits of Mount Myoboku's Senjutsu.

"Got it!"

Jiraiya replied, took a deep breath, and closed his eyes.

He tried to recall what it had felt like when Sage Fukasaku guided him at Mount Myoboku, attempting to sense the elusive energy around him.

The laboratory fell quiet. Only the instruments' faint humming broke the silence.

A moment later—

The sides of Jiraiya's nose began to swell slightly, and faint, oil-paint-like markings appeared beneath his eyes. They were Toad features.

An energy utterly unlike his own Chakra began to gather inside him.

But just as those features were about to grow more pronounced and his Senjutsu Chakra was about to take shape, Jiraiya abruptly opened his eyes. The changes in his appearance faded with them.

He panted a few times, his face showing a hint of disappointment.

"Whew... This is about as far as I can get for now."

"If I go any further, I can't control the changes in my body. It feels like I'm about to turn into a Toad completely."

Orochimaru nodded calmly and signaled for the Shadow Clones to record the data.

"Mm. You've got the basics of sensing and guiding it down."

After that, he had Jiraiya make several more attempts at different intensities. For example, he had him deliberately speed up the absorption or try to perform a simple Chakra Nature Transformation while gathering Senjutsu Chakra.

Each time, the instruments recorded detailed data.

Jiraiya didn't really understand what was going on, but he cooperated obediently.

After putting him through the wringer for quite a while, Orochimaru finally called it.

Jiraiya jumped down from the platform and stretched his stiff body. Then, curiosity got the better of him, and he edged over to Orochimaru to study the complicated curves and numbers on the screen.

"Well? How was it? I've got decent talent, right? I'll be able to master Sage Mode in no time, won't I?"

He rubbed his hands together, looking hopeful.

"You don't actually think this little data is enough, do you?"

Orochimaru glanced at him and replied blandly.

"Huh? We have to do more?"

Jiraiya's grin froze on his face.

"Research isn't as simple as you think."

Time passed, and a year slipped by amid constant experiments and the accumulation of data.

It was also the third year since Orochimaru had come to this world and become a Konoha Ninja.

After a year of research together, especially with Orochimaru occasionally "borrowing" Jiraiya for various "harmless" tests, his research into Senjutsu had finally gotten on track.

First, just as he had expected, sensing and absorbing Natural Energy required the body and mind to reach an extremely "still" state.

The shinobi of the Naruto world actually lacked this ability because they relied too heavily on Chakra, such a "convenient" form of energy.

Once Natural Energy entered the body, it instinctively clashed with Chakra—a reaction rooted in the fundamental nature of the two energies.

That might be the fundamental reason why people with special constitutions like Jugo, who could absorb Natural Energy innately, would periodically fall into a frenzied state.

Their bodies struggled to remain stable as two completely different energy systems clashed within them.

The core secret behind the Senjutsu of the two Sacred Lands, Mount Myoboku and Ryūchi Cave, was just as he had suspected.

They hadn't created an entirely new way to use energy. Instead, by imitating the traits of the Toads and Snakes—those sages who had adapted to or even mastered Natural Energy since ancient times—they greatly reduced or even harmonized the body's rejection of it.

They allowed the human body to "accommodate" this powerful, native force.

As for how they managed it, all he could do for now was speculate that it had to do with the special nature of Senjutsu Chakra.

It made sense, since Chakra already showed similar properties in this regard, as with Impure World Reincarnation.

When the Chakra of the dead was attached to a living person, that person could use the dead person's Ninjutsu. They could even wield Kekkei Genkai such as the Sharingan and Rinnegan.

So it wasn't impossible that Senjutsu Chakra could gradually help a host adapt to Natural Energy...

"So the key is still figuring out how to make the body adapt..."

Orochimaru studied his research notes, deep in thought.

After understanding this, he selected and adapted some basic training methods from The Outcast world and taught them to Jiraiya.

When it came to reaching a state of "stillness" and adjusting one's inner Qi, the methods of The Outcast world were far ahead of the rest.

Although the bodies and minds of shinobi in the Naruto world were strong, they mostly used those abilities to control Chakra and perform Ninjutsu. They had little experience with this kind of purely internal training.

At first, Jiraiya was skeptical. He couldn't see what good all those strange poses and breathing techniques could possibly do.

But after trying them for a few days, he was a convert.

The results were surprisingly good!

He found that his efficiency at sensing Natural Energy had improved, as had his stability when gathering Senjutsu Chakra. Even his control over Chakra had improved significantly.

After about a few months of combining The Outcast world's training methods with the plan Orochimaru had given him, Jiraiya was delighted to discover that he had actually managed to enter Sage Mode!

He still couldn't maintain it for long, and the features were somewhat unstable, but it was an undeniable breakthrough!

After confirming that these methods worked, Orochimaru used them as bargaining chips. Through Jiraiya and his own connections, he managed to obtain tiny samples of the White Snake Sage's and the Toad Sage's bodily tissues from Ryūchi Cave and Mount Myoboku.

The process went even more smoothly than he had imagined. The White Snake Sage seemed curious to see how far he could go and agreed readily.

What surprised him was Mount Myoboku. The Great Toad Sage met with him in person and said that in its prophecy, it had seen him bring change to the Ninja World. That change might bring New Life, or it might bring Destruction.

It was willing to give him a small sample of its bodily tissue, but only if he agreed to a condition: if the Ninja World ever faced danger, Orochimaru had to do everything in his power to stop its destruction.

Orochimaru was taken aback. After giving it some thought, he readily agreed.

That was how he obtained tissue samples from the two sages.

For the next half year or so, Orochimaru devoted most of his energy to studying these two types of cells, and he made considerable progress.

"Next, I should start thinking about the next goal.

It's time I found a way to get my hands on the Second Hokage's research materials on Impure World Reincarnation."

A glint flashed in Orochimaru's eyes. After that, he would need to figure out how to get the research materials from Danzo.

Taking a deep breath, Orochimaru pushed open the laboratory door. The long-absent sunlight made him squint.

Come to think of it, he'd been cooped up in the laboratory for ages...

He wondered how Tsunade and Hiruko were getting on with their work.

To train more medical ninja, he'd had those two try to organize and compile materials, then put together some textbooks.

But he hadn't checked on them in a while. He had no idea how far they'd gotten...

After several years of development, Konoha was noticeably livelier than when he had first arrived.

The desolation and oppression of the war years had faded. Children's laughter echoed through the streets and alleys, breathing new life into the village.

Though there'd be another war in a few years...

Orochimaru walked slowly down the street, savoring this hard-won peace.

A little while later, he arrived at the Hokage Building.

Today, his teacher, Third Hokage Hiruzen Sarutobi, had specifically summoned the three of them.

Hiruzen hadn't said what the meeting was about in his message.

But Orochimaru could tell it wouldn't be an ordinary D-rank or C-rank mission.

When he entered the Hokage's office, two familiar figures had already arrived.

"Hey, Orochimaru! You finally emerged from seclusion!"

Jiraiya saw him come in and immediately waved enthusiastically.

After spending this time researching Senjutsu together, he and Orochimaru had grown much closer. They'd gone from teammates to best friends.

Tsunade, on the other hand, folded her arms and pursed her lips, a trace of barely perceptible resentment in her eyes.

Orochimaru had spent nearly every waking moment in the laboratory lately. Several times, she'd wanted to discuss new ideas about Medical Ninjutsu with him—or simply drag him out to gamble—but she hadn't even been able to find him.

That guy was even more of a homebody than her second granduncle!

Young people had it good...

Hiruzen Sarutobi sat behind his desk, watching the little exchange between his three students with a warm smile.

But soon, his expression turned a little more serious.

"You're all here. Let's get down to business..."

Hiruzen Sarutobi tapped the pipe in his hand against the ashtray.

Then he took a form from his desk drawer and set it on the desk.

"Take a look."

Orochimaru, Jiraiya, and Tsunade leaned in to examine it.

At the top of the form, in prominent lettering, it read: "Five Great Ninja Villages Joint Chunin Qualification Exam Application Form"...