Due to various reasons, the power level of the ninja world is constantly declining, and the upper limit of enduring extraordinary power is not high. This can be seen from the drawbacks of the Sage Mode in the Mizuki version. The ninja world is indeed suppressing the birth of too strong power, such as the Rinnegan, the Samsara Eye, and so on.

As the most powerful Six Paths Sage in the ninja world, it is impossible that he did not notice this.

Neither of Kaguya Otsutsuki's two sons inherited the Rinnegan, a world-destroying eye technique.

The descendants of the Six Paths Sage were unable to pass on even the Rinnegan. No one could inherit the Sage's body and eyes completely. Even the Rinnegan was degenerated into another bloodline limit eye technique - the Sharingan, which had good combat power but greatly weakened its influence on the ninja world.

The secret techniques of the Mangekyō Sharingan, whether it is Amaterasu, Tsukuyomi, Kamui, or even the forbidden techniques of Izanami and Izanami, are not much worse than the Rinnegan, but the most crucial point is that the authority to control the Ten Tails, that is, the Sacred Tree, is stripped away; the power of the Rinnegan that can bring the dead back to life, can only be slightly compared to the forbidden technique of Izanami; other abilities to control gravity, mind, soul, memory, chakra and Yin-Yang escape are all gone.

The Rinnegan should not appear again. It is not only the objective conditions in the ninja world and Mizuki's opinion that make it so, but the Six Paths Sage has also imposed restrictions through practical actions. The distinction between yin and yang chakra is a clear proof of this. For thousands of years, no one has ever been able to gather the power of yin and yang to open the Rinnegan, until Uchiha Madara encountered an accident due to Black Zetsu's plan.

Another clue is the Ten Tails. After extracting its chakra, it was split into nine tailed beasts using Yin-Yang Release. The Six Paths Sage's intentions were undoubtedly good. Although their birth was not very glorious, the essence of the nine tailed beasts is indeed the collective product of human will. The Ten Tails once said that he is natural energy. Although this is not accurate, it did not lie.

Mankind's contribution to natural energy is manifested in the form of the tailed beasts. The Six Paths Sage created the nine tailed beasts not just to create a super-powerful force to protect mankind through the dangerous barbaric times.

The three major summoning beast sanctuaries have inherited the Sage Mode, and they are able to filter and utilize natural energy very well. However, when humans came to dominate the ninja world, big problems arose.

At the beginning of human beings, the ninja world had already declined extremely, but there was still an existence like the sacred tree that constantly absorbed natural energy.

From the very beginning, humans have been in an extremely unfavorable situation. Not only are humans with poor qualifications unable to use natural energy, but their own paths to mastering extraordinary powers are also extremely narrow.

The Six Paths Sage is divided into yin and yang, and can also be said to restrict the Rinnegan. Then why was the five elements of earth, water, fire, wind, and thunder ninjutsu born?

In fact, the answer is not difficult to guess, because this time the spirits of all things have been so weak that most individuals are unable to use the power of chakra. As a last resort, the Six Paths Sage left a backup plan and passed down the concepts of hand seals, five elements, and ninjutsu. Chakra itself has no attributes, but humans have to use secondary powers such as hand seals and ninjutsu according to their own qualifications.

You know, when did the Six Paths Sage Otsutsuki Hagoromo and his brother Otsutsuki Hamura use chakra, they needed to classify the attributes of the seals? Freely controlling all chakra changes and affecting its form and nature is only one's own will, not any physical qualifications.

Humanity as a whole is no longer able to control the power of chakra, and has to pass on the use of chakra in the form of the five elements. Then, won't the natural energy, the greatest treasure for humans, be even more unusable? Coupled with the influence of the sacred tree, the "bad record" of human betrayal in the past basically eliminates the possibility of using the power of the Sage Mode.

Without considering unexpected help like the Summoning Beast Sanctuary, the purpose of the Six Paths Sage in creating the Nine Tailed Beasts, through this series of clues, a vague thread surfaced in Mizuki's mind.

The nine tailed beasts were most likely arranged by the Six Paths Sage to help humans learn to use natural energy and control similar powers of immortal arts. This was the most likely explanation after Mizuki sorted out the information and speculations.

"There is toad oil in Myoboku Mountain, and humans have tailed beasts. Only my method of practicing Sage Mode is orthodox, even though it's a little off the track!"

There is nothing wrong with the methods provided by other intelligent races, just like a car, adding different brands of gasoline, most of them can run fast and well, but the most suitable one is always the best brand when the car is designed, which is not only easy to use, but also does not damage the engine. The nine tailed beasts are the bodyguards and nannies customized by the Six Paths Sage to escort humans, plus the enlightenment and protection medium of using the Sage Mode.

Too bad humans messed it all up.

In the Fourth Ninja War, the powerful strength displayed by Uzumaki Naruto was not only able to identify malice towards humans, but also able to distribute the power of the Nine-Tails to many people for protection. The combat power of the Nine-Tails was enough to directly confront Uchiha Madara. That was a model of joint combat between humans and tailed beasts.

As for Shuimu, unfortunately, the difference in souls made Shuimu choose a violent and wrong way of use, and disadvantages were inevitable.

Therefore, Mizuki wanted to experiment on the indigenous people of the Ninja World to find out how humans and tailed beasts would get along as predicted by the Six Paths Sage, and how to achieve stable and safe use of natural energy.

"It is definitely not enough to just use the tailed beast chakra as a medium to sense and absorb natural energy. I have proven it through my own experience!"

Mizuki had no way of trying to figure out what to do. Without using the tailed beast's chakra to absorb natural energy, he didn't even have the ability to sense it. The reality made Mizuki quite helpless, so he had to think about Sakura.

"You didn't come here just to tease me, did you?"

"Of course it's something important!" The clone said with a smile, "Exchange memories first, and you'll know."

…

A quarter of an hour later, Shuimu's real body experienced it carefully for a while.

"Has the change in the nature of Chakra's third attribute - lightning - been completely completed? It's been almost half a year, it's really slow!"

"I wasted a lot of time on other things. It's going to be difficult to develop attributes that I'm not good at."

Shuimu nodded. In fact, the clone came this time just to confirm what to do next!

"Let's develop the wind attribute first. The water attribute is too unfamiliar..."