Discovering the arrival of Boruto and Kawaki, Code also extinguished the thought of continuing to play around. He immediately summoned a large number of his Zetsu-like puppets, directly overwhelming and killing all the experimental subjects except for Ichi and the three beside him.
Ichi, clutching his severed arm, quickly retreated. Code suddenly burst out from a puppet's body. Caught off guard, Ichi was also hit. If he hadn't reacted quickly, his head would likely have been severed.
Just then, a sharp pain came from the side. In his peripheral vision, the white-haired youth who had attacked their village was lunging towards his vitals at a terrifying speed.
Clang!
A sound of metal clashing rang out.
A dark-textured rod had narrowly blocked the enemy's claws. When he saw the appearance of the newcomers, his face couldn't help but show astonishment. Konoha's... and two brats at that... What terrified him even more was their strength. Watching the blond brat fighting evenly with Code, if he remembered correctly, this brat seemed to be the son of Konoha's Seventh Hokage. But according to the village's intelligence, wasn't this brat just a good-for-nothing second generation?
"If you don't want to get caught in the crossfire, stay far away from here," Kawaki said coldly.
Ichi paused, stunned. When was the last time he had heard similar words? It seemed to be when he had just become a Genin. Looks like those guys can proceed to the next stage of experiments... Thinking this, he sped away into the distance with swift strides.
Kumogakure, the Village Hidden by Clouds.
Ninjutsu Research Lab.
The thick walls couldn't block out the roars from Boruto and Code's battle.
Naruto sat leisurely in an office chair, unhurriedly flipping through Kumogakure's latest research findings.
"Manufacture Otsutsuki cells into a nutrient-like solution, inject it into the human body, and by leveraging the Otsutsuki's formidable abilities, cultivate ninja adapted to the new era..." Reading this, Naruto couldn't help but marvel. As expected of Kumogakure, always daring to be the first in the world.
Actually, if one were to seriously trace it back, the first to do this kind of thing was Konoha. The cultivation of substitutes for the First Hokage, Senju Hashirama, had never stopped after the First's passing, using similar methods. It was only when the First Hokage's granddaughter, Senju Tsunade, succeeded as the Fifth Hokage that these experiments gradually ceased. Later on, Konoha had Uzumaki Naruto, and the cultivation of First Hokage substitutes, with its disproportionate input and output, officially became history.
As for experimental materials? Otsutsuki Momoshiki, Otsutsuki Kinshiki, Otsutsuki Urashiki—Kumogakure had more than enough opportunities to obtain materials. However, it had been less than a year since Kinshiki's appearance, yet Kumogakure's Otsutsuki experimental subject cultivation had already achieved such success. It was hard not to suspect they had contingency plans long ago.
"And this..." Naruto picked up another research paper from the table, a trace of admiration flashing in his eyes. "[On the Conversion of Natural Energy and Chakra]."
Before the concept of Otsutsuki Kaguya, the progenitor of chakra, became known, almost all ninja believed that "chakra" was a mixture of physical energy generated by the body's one hundred and thirty trillion cells and spiritual energy. The amount of chakra was directly proportional to the strength of both physical and spiritual power.
But after gaining a deeper understanding of natural energy, Naruto found this statement to be biased. A more accurate statement would be: when a person's physical and spiritual strength are sufficient, a ninja can better draw upon the external natural energy of the world, which, in the form of a trickle, strengthens the chakra within the ninja's body.
The reason chakra became the dominant power in this world was because the Sage of Six Paths had shared it with the world through 'Ninshū'. If the chakra shared by the Sage of Six Paths could last for thousands of years and continue to spread and grow without external interference, it would clearly be unreasonable.
The God Tree, also known as the Ten-Tails, was the Otsutsuki clan's energy extraction device. It could convert all the energy of a planet into chakra and bear a Chakra Fruit. And the most abundant energy on a planet was undoubtedly natural energy.
After using natural energy for an extended period, Naruto had confirmed one thing: his chakra would unconsciously absorb and assimilate external natural energy, thereby strengthening itself. But this assimilation was very weak, so weak that he might not even notice it if he didn't observe carefully. During training, the speed of this assimilation would increase noticeably. This speed also varied considerably among different ninja due to differences in physical fitness and spiritual energy. It could even be said that the chakra extraction techniques passed down through generations of ninja were, in fact, weakened versions of sage art secret scrolls. Chakra was a key; it gave many people who couldn't normally access natural energy, cultivate senjutsu, or become sages, another chance to become superhumans.
Kumogakure's research in this area was undoubtedly epoch-making. They directly extracted pure natural energy from nature and converted it into a 'nutrient solution' easily absorbed by the human body, for direct injection. They had even strictly defined the dosage and injection intervals for ninja of different levels to help Kumo nin reach their peak at the fastest possible speed.
Naruto slowly turned to the last page—[Prosperous Land Plan]. Within Kumogakure's territory, install large-scale natural energy conversion devices to improve the fundamental quality of Kumogakure ninja.
Setting aside the Otsutsuki experimental subjects, just this natural energy conversion plan alone... If Konoha continued to maintain its traditional ninja cultivation methods, Naruto had every reason to believe that after the Seventh Hokage and Uchiha Sasuke passed away, Kumogakure would replace Konoha as the new hegemon. Of course, if Konoha continued to 'use hacks' (referring to their exceptional talents and plot armor), then that would be another matter.
"'A bountiful harvest.'" Naruto smiled faintly and packed up all the research findings from this institute. Perhaps he had already found a low-cost way to 'abduct' Snake Uncle. Speaking of which, what earth-shattering research results had the Snake Uncle of this era produced? But on second thought, he decided against it. He and Konoha were still in their honeymoon period. Boruto, Kawaki, plus the Seventh Hokage and Uchiha Sasuke, and Snake Uncle whose combat strength was still unknown... This honeymoon period had to be maintained.
"Both sides are about at their limit." Naruto's eyes seemed to pierce through walls, observing the battle between the three. Chakra, after all, was not senjutsu; its use couldn't restore the body or spirit. On the contrary, the more intensely chakra was used, the more fatigued the body and spirit became. Although both sides could use the puppets to recover chakra, they couldn't recover from physical and mental exhaustion. He was very curious: would the two secure a decisive victory and kill Code, or would Code turn the tables in a desperate counterattack, or perhaps escape?
Naruto took out Karasuki and slowly infused chakra into it. Regardless of the outcome, the events of this world would no longer concern him. Having trained Boruto and Kawaki for so long, if they couldn't even win a battle with such an advantage, they might as well go to the Pure Land and receive training from the Sage of Six Paths.