Rasengan

"All right, Karin's back. Let's go upstairs."

Karin had grown increasingly accustomed to life in Konoha. The timid, submissive nature she had developed among the Grass Ninja had vanished completely, replaced by that of a carefree little wild child.

Yumi was rather worried about this, afraid the girl would not be able to get married in the future. Aoba, on the other hand, did not feel much about it.

"Don't worry. When a girl grows up and meets someone she likes, she'll naturally change. Parents don't need to worry too much. Generally speaking, the more you interfere, the more likely you are to make things worse."

"I hope so." Yumi was still a little uneasy.

"Mom, is dinner ready? I'm starving."

After spending the entire afternoon running wild, Karin noisily demanded food. Yumi looked helpless, but she still went to cook for her with indulgent affection.

Karin, meanwhile, latched onto Aoba.

"Big Brother Aoba, can you teach me a few more powerful ninjutsu? I've already practiced the Three Basic Techniques until I'm very proficient. I can climb trees and walk on water too."

"Really? Then let me see."

In the original manga, most of Karin's scenes involved her fawning over Sasuke. There were very few depictions of the girl's growth.

Later, she followed Orochimaru. And given Orochimaru's temperament at that time, he was likely already pursuing the path to immortality.

There was no way he would seriously teach her. Yet even so, Karin still became part of the management of one of Orochimaru's bases.

Therefore, Aoba had known from the very beginning that this girl was a genius the original story had never properly revealed.

But little Karin's performance still surprised him.

After all, only about half a year had passed since she started school. Even if she had some foundation, completing the school curriculum so quickly still astonished him.

Sure enough, under Aoba's watchful eyes, Karin skillfully demonstrated the Three Basic Techniques, as well as tree climbing and water walking.

"Very good indeed. You can begin the next stage of training."

In fact, it was not just those basic skills. The chakra within Karin's body had already surpassed the level of an ordinary Konoha Genin.

The Uzumaki physique was truly so powerful that it was shocking.

Taken as a whole, Aoba even felt that the Uzumaki were the clan closest to possessing a Sage Body. Aside from Hashirama Senju, the rest of the Senju were rather mediocre in terms of physique.

Aoba had long prepared for Karin's next stage of training. He had previously tested her chakra affinities. The girl's affinities were earth and water.

Aoba was not skilled in either of them. However, the path he had planned for Karin was not that of a purely conventional ninja.

After all, the original story had shown it as well. Karin possessed the most distinctive traits of the Uzumaki. Her Mind's Eye of the Kagura had already awakened.

Beyond that, in the later stages of Naruto, Karin had also awakened Adamantine Sealing Chains, a sealing jutsu that required innate talent to perform.

This showed that Karin's true direction should be Sealing Jutsu. In the Naruto World, high-level Sealing Jutsu, when used well, was no weaker in combat than pure ninjutsu.

In terms of potential, it even far exceeded conventional Five Element Ninjutsu. After all, the Uzumaki's Sealing Jutsu might be able to touch upon the Reaper.

During his previous transaction, Aoba had acquired a great deal of Sealing Jutsu material from Orochimaru with this in mind. Sooner or later, he would inevitably face Tailed Beasts.

Conventional ninjutsu had little effect against the Tailed Beasts' overwhelming brute-force style. But the Uzumaki's Adamantine Sealing Chains and Eight Trigrams Sealing Style could be said to specifically counter Tailed Beasts.

When that time came, Karin would be the trump card in his hand.

Karin soon regretted it. Compared to physical training like tree climbing and water walking, Sealing Jutsu training involved a vast amount of specialized knowledge.

In other words, Karin had to start by studying a huge amount of theory.

Heaven pity her, but the thing Karin feared most at school was all that messy theory. She had thought that after returning home, she could learn some impressive skills to show off to her friends.

Instead, she had to study the theory classes she hated most. And those theories were obscure and difficult to understand, even more sleep-inducing than the Will of Fire at school.

But there was nothing she could do. She had asked for it herself, and Big Brother Aoba had agreed. It was already too late to back out. Her only way of resisting now was to play outside a little longer after school.

Because once she returned home, her dark and miserable life of studying would begin.

Karin's studies had entered the proper track. Aoba, too, seized every second to improve himself.

After completing Sage Mode, his need for conventional ninjutsu had increased. After all, under Sage Mode, even some ordinary ninjutsu could become exceptionally terrifying.

Civilian ninjas had very few ways to obtain ninjutsu. Under normal circumstances, they completed missions to accumulate points, then exchanged them with Konoha's higher-ups.

Completing high-level missions could also earn ninjutsu as rewards. Another way was through spoils taken in battle.

But Aoba did not need either of those. He had his own channel: Kakashi.

As Konoha's renowned Elite Jonin, Kakashi likely knew more ninjutsu than anyone except the Third Hokage, perhaps even surpassing him in sheer number.

Previously, Aoba had mostly used Nintaijutsu in battle to conserve chakra. With Sage Mode greatly increasing the power of his ninjutsu, he learned quite a few techniques from Kakashi to supplement and expand his combat methods.

Of course, he was not taking advantage of Kakashi for free. He gave Kakashi two Life Potions. Used well in actual combat, those things were a second life. More importantly, they had no side effects whatsoever, making them valuable enough to match some ordinary ninjutsu.

At the same time, Aoba was also trying to learn one of the most famous ninjutsu in Naruto: the Rasengan.

The Rasengan's original concept had actually come from the Tailed Beast Ball. Compress chakra to the extreme, then release it.

But in reality, ninjas simply could not accomplish that. Humans could never possess as much chakra as a Tailed Beast, and even if they did, they could not compress it to that extent.

A Tailed Beast Ball did not require some special technique. It was genuine brute force, demanding extreme amounts of chakra and extreme compressive power.

Without sufficient compressive force, a chakra sphere could not produce any damage. Once chakra left the human body, it rapidly dispersed.

That was why ninjutsu existed. Ninjutsu changed chakra's form, turning it into matter or energy. Only then could it be released at range.

Minato Namikaze realized this and changed his approach. He tried to make chakra rotate in his hand, using that rotation to maintain stability while also achieving a compressive effect.

That was the basic principle of the Rasengan. Now that Aoba knew its basic principle, he naturally would not let this technique pass him by.