Myriad Spirit Longevity Art

In the Underworld, on a secluded hill, floated a man with two horns on his head, brown hair, and a white robe. Six black tomoe-shaped markings adorned his chest, and a red spiral symbol marked his back, beneath which tomoe were arranged in a nine-square grid. Nine Truth-Seeking Orbs formed a circle behind him. This was the Sage of Six Paths, floating cross-legged in midair.

After the Sage of Six Paths died, his soul came to the Underworld like any ordinary person's. He found this peaceful place to live and kept watch over the Shinobi World.

The moment a Truth-Seeking Orb appeared behind Naruto, the Sage of Six Paths, who had been floating with his eyes closed, opened all three of them. A puzzled look crossed his face as he began to investigate.

But the Truth-Seeking Orb behind Naruto appeared for only an instant before vanishing. After investigating without finding anything, the Sage of Six Paths closed his eyes again.

Once Naruto fully activated Sage Fox Mode, a powerful aura radiated from him, battering the surrounding space and stirring up gusts of wind all around him.

When shadows appeared around Naruto's eyes, Jiraiya, standing nearby, sensed a familiar energy. "Is that Natural Energy? Sage Mode?"

After Kurama's seal was undone, the two of them were of one mind. Kurama's spiritual energy carried no negative emotions; instead, it gave off a warm feeling.

After taking a moment to sense the changes in his body, Naruto opened his eyes. He felt incredibly strong. Just how strong? Take his earlier fight with Kakuzu: if he'd been able to use Sage Fox Mode then, he might have beaten Kakuzu without needing a second move.

After Naruto and Kurama became one in mind, Naruto gained some new knowledge, including how to use a Tailed Beast Bomb.

Naruto raised his right hand. Red and blue spheres of spiritual energy appeared in the air. Under his control, they slowly merged, eventually forming a black sphere that hovered above his palm.

The instant the Tailed Beast Bomb coalesced in Naruto's hand, the ground beneath his feet cracked. Then, as if struck by a heavy object, the ground within a three-meter radius of him sank about thirty centimeters.

Rather than throw the Tailed Beast Bomb, Naruto controlled it until it dissipated in his hand. He didn't try out any other abilities either, instead leaving Sage Fox Mode since Jiraiya was still waiting nearby.

When Naruto returned to normal and opened his eyes, Jiraiya stepped forward and asked, "Naruto, were you using Natural Energy just now? It felt a lot like Sage Mode."

"Yeah, it has to do with Natural Energy, but I call it spiritual energy," Naruto said.

Seeing Jiraiya's confusion, Naruto continued explaining. "That was an ability I gained after Kurama's seal was undone. You can think of it as the true Perfect Jinchuriki Mode."

"As for Sage Mode, that's because I awakened a Sage Body. And I don't cultivate chakra in my daily training; I cultivate spiritual energy, which is what you call Natural Energy."

That only confused Jiraiya more. He'd trained in Sage Mode himself and knew how dangerous Natural Energy was. At Mount Myoboku, as far as anyone knew, only Sage Fukasaku and Sage Shima had Sage Bodies, thanks to living there since childhood and being constantly exposed to Natural Energy. Though Jiraiya was called the Toad Sage, he couldn't use Natural Energy in his daily life. Whenever he needed it, he had to first gather Senjutsu Chakra to enter Sage Mode. To maintain it in battle, he also had to summon the two sages to assist him.

"How did you manage to cultivate using Natural Energy?" Jiraiya asked.

Having trained in Sage Mode himself, he knew how dangerous cultivating Natural Energy could be. Humans training in Sage Mode at Mount Myoboku risked turning into frogs or stone statues. When Jiraiya had trained, Sage Fukasaku had watched over him, knocking the Natural Energy out of his body with a special stick whenever he started turning into a frog and lost control. As a result, Jiraiya had taken quite a few whacks from Sage Fukasaku.

It had taken Jiraiya a full twelve years to learn Sage Mode, and he still hadn't mastered Perfect Sage Mode. Whenever he used Sage Mode, signs of frog transformation appeared on his face. Minato Namikaze, his student whom he believed to be the Child of Prophecy, had taken three months even with Jiraiya's guidance.

And that was with Natural Energy abundant at Mount Myoboku. After Jiraiya learned to draw Natural Energy into his body without losing control, he'd tried training in Sage Mode elsewhere, but his progress was slower than at Mount Myoboku. He'd found that Natural Energy was less plentiful outside the mountain.

The abundance of Natural Energy at Mount Myoboku was also why many of its toads were so large. Jiraiya himself was tall because he'd spent much of his youth there. The toads of Mount Myoboku also lived exceptionally long lives. The two sages, for example, were already over eight hundred years old. And the Great Toad Sage, the mountain's master, had lived since the time of the Sage of Six Paths and had even taught him Sage Mode.

"Pervy Sage, you know a lot about meridians and acupoints, right? I learned something called cultivation arts. They let you draw spiritual energy into your body in a special way and gather it within you. Once inside, the energy circulates through your meridians and acupoints, strengthening your body," Naruto replied.

Jiraiya hurriedly asked, "Doesn't the spiritual energy you absorb dissipate?"

When Jiraiya used Sage Mode, the Senjutsu Chakra he gathered would dissipate on its own before long if he didn't use it.

"No, because cultivating an art lets you form a vortex inside your body. When you're not using the spiritual energy, it circulates within that vortex," Naruto answered.

"Cultivating can also expand the vortex and make the spiritual energy more concentrated. It can even transform your body into a spiritual body. Actually, Pervy Sage, your Sage Mode works by absorbing spiritual energy and temporarily giving you a spiritual body." Seeing Jiraiya lost in thought, Naruto added, "That's how it works."

Hearing Naruto's explanation, Jiraiya suddenly understood. He continued questioning him. "Then your body is a spiritual body now, right?"

"Cultivating an art gradually changes your body. Once it reaches a certain point, it transforms into a spiritual body. Spiritual bodies have different effects, too. Mine doesn't boost my combat power much; its main purpose is to speed up my training. I call it the Spirit-Absorbing Battle Body," Naruto replied.

"I see. No wonder you're so strong at your age," Jiraiya said.

Just then, Naruto looked up at Jiraiya, his expression suddenly solemn.

Naruto's serious gaze made Jiraiya straighten up as well.

When Jiraiya's expression turned uneasy, Naruto said, "Pervy Sage, would you like to have a spiritual body and become a true sage?"

Still feeling awkward under Naruto's stare, Jiraiya asked in astonishment, "Can I?"

"Of course! I've already prepared a cultivation art for you, Pervy Sage. And I've got some other interesting things for you, too," Naruto replied with a mischievous grin.

Seeing Naruto's slightly unsettling smile, Jiraiya swallowed. He wanted to become a true sage, but if Naruto asked him to do something against his will, he wouldn't agree. He watched Naruto warily.

Naruto noticed Jiraiya's wary expression and burst out laughing. "Haha, Pervy Sage, I was just messing with you. I really have prepared something good for you."

With that, Naruto stood up and walked over to Jiraiya. He told Jiraiya to stay still, then touched a finger to his forehead. Jiraiya closed his eyes.

The cultivation arts in Naruto's mind were written in the language of another world.

So when he chose an art, he had converted its text into the writing currently used in the Shinobi World.

After a long while, Naruto lowered his finger. A book called the Myriad Spirit Longevity Art had appeared in Jiraiya's mind. It wasn't an art for increasing one's cultivation, but one for healing injuries—or, more precisely, replenishing life force.

Plants and trees in the world constantly released a kind of energy called Wood Spirit Qi, brimming with vitality. It was especially abundant in places with lush vegetation. That was why people felt refreshed and invigorated in scenic, beautiful places.

Wood Spirit Qi couldn't normally be seen; it could only be sensed through special means. Naruto had cultivated the Myriad Spirit Longevity Art himself, but since he didn't need to replenish his life force and had never been injured, he hardly ever used it.

When Naruto had absorbed Asura's chakra back then, he'd immediately awakened the Uzumaki Clan's bloodline and gained a spiritual body. That was because Asura's chakra was an exceptionally concentrated and pure form of foreign spiritual energy.

Jiraiya was now over forty. He'd trained for nearly forty years, using chakra the entire time. Chakra was produced by mixing spiritual energy and physical energy in equal amounts. In other words, producing even a little chakra required an equal expenditure of spiritual energy and physical energy, both of which were manifestations of life force.

In the world Naruto remembered, the stronger a person became, the longer they lived and the younger they looked. Cultivation arts not only made people stronger, but could also extend their lives once they reached a certain level. Jiraiya was one of the Shinobi World's top fighters, but though he was only in his forties and still had a sturdy build, wrinkles had already begun to appear on his face.

In theory, cultivation worked by absorbing spiritual energy to strengthen the cells that made up the body, increasing their vitality and the number of times they could divide. Once someone reached a certain level, their cells stopped dying. They would divide slowly until they eventually stopped dividing altogether. Though the cells could still be injured, they would no longer die, and they could recover by absorbing spiritual energy. At that point, one truly shared the lifespan of heaven and earth: as long as spiritual energy existed, one would never die.