'Huh'

Zhou Yu used the Flying Thunder God to smoothly move the space of the Nine Little Strongs to his doorstep.

"Naruto, Sasuke, everyone will be gathering in a week, we're going back."

The departure of Zhou Yu and the others can make the people who follow behind to protect look stupid, what about people? Where have all the people gone? I can only hurriedly report to the three generations, and the three generations smiled when they found out and let those people go back, saying that Zhou Yu Naruto and Sasuke don't care.

Iruka spends seven days at the exit at the edge of the survival drill forest, otherwise Iruka will definitely be surprised to find on the streets.

Seven days later, Zhou Yu took Naruto and Sasuke back to the survival exercise forest to successfully pass the survival exercise, Iruka saw Zhou Yu and Naruto and Sasuke who came out at the end and praised them fiercely, because Zhou Yu and Naruto and Sasuke persevered to the end, and the other classmates in the class gave up a day or two early and three or four days late, only Zhou Yu, Naruto, and Sasuke persevered to the end, and Zhou Yu, Naruto, and Sasuke were very happy to receive Iruka's praise.

In the second half of the fourth year, Iruka didn't make any mistakes, and he studied normally, took exams, and finished.

After Zhou Yu's survival exercise, he devoted himself to soul research and soul sealing research, and the collection of experimental material information was all done by Zhou Yu, and he devoted himself to research.

There are two major sources of pollution in the soul energy, one is the evil qi, which kills a lot and does not know how to eliminate it, and the soul energy that is entangled by the evil qi will become a machine that only knows how to kill people, and the other is the memory fragment of the soul body itself, which will split the personality if it absorbs too much.

Zhou Yu estimated that the positive energy had an effect on it, but the Hokage World went there to find positive energy, and Zhou Yu also tried to use Fire and Thunder to expel the evil energy, and the result was very ideal, the evil energy was gone, and the soul energy was gone, and Zhou Yu knew that with his current knowledge reserves, he couldn't deal with the evil energy, so he could only solve the other one first.

Memory fragment Zhou Yu still worked the soul cutting line, since it is a fragment, it will become more shattered! If you can't cut it, you should crash and smash it! It is still the principle of soul cutting, controlling the chakra to form two chakra discs, the surface of the disc is engraved with the upper destruction soul sealing technique, the two discs are against the gray soul energy group containing memory fragments on the left and right, sooner or later the memory fragments can be smashed and disappeared, of course, this is Zhou Yu's ideal state, it depends on the experiment, if it doesn't work, you can only wait for the next world to learn the spell, Zhou Yu is very fond of a spell to take the mind, The ability to obtain emotions and memories from a person's mind, the memories in the brain and the memory fragments in the soul may be much worse, but there should always be some connection, and there will always be time to solve the connection.

The soul smashing disc does have some effect, the gray soul energy group that was collided by the two soul crushing discs is obviously much lighter, and Zhou Yu found that the memory fragments in the soul of the middle ninja level are tougher than the memory fragments in the soul of the lower ninja level, whether it is the cutting of the soul cutting line or the collision of the soul crushing disc, the number of collisions and collisions of the memory fragments of the middle ninja level is higher than that of the lower ninja level soul fragment cutting and collision, The memory fragments in the soul of the upper ninja level are significantly stronger than the memory fragments in the soul of the middle ninja level, and it seems that the ninja advancement is not only the change of chakra, but there is a lot to study.

The experiment outside the village has also made a lot of progress in nearly a year, ordinary people are very prone to accidents when they fuse the soul energy of the ninja who is higher than their own soul level, and the soul will collapse if it exceeds one-fifth of their own soul energy, and the soul has collapsed before the side effects appear, and the old and promising lower ninja has made significant progress in Chakra after fusing the lower ninja soul, and the lower ninja will quickly have negative reactions when fusing more than one-third of their own soul energy, and there will often be no negative reactions for several months before one-third, And more than a third of the negative reaction will appear quickly within a month, the more the soul merges, the faster the reaction appears, the early often have nightmares, when killing, will go berserk, more than half will collapse, lose self.

The data of soul research gave Zhou Yu a lot of warnings, at least don't fuse too much soul energy at a time, let alone try to fuse soul energy higher than your own soul level, fusing soul energy of the same level should not even exceed one-tenth, one-tenth is already a terrifying ratio, and a reasonable proportion must continue to experiment.

During the vacation of the fourth grade, Zhou Yu did not go out to practice with Naruto and Sasuke, except for the shadow-level ninja who can make the three of them progress, the rest of the going out is a waste of time, and the shadow-level ninja can't afford to provoke except for Konoha, and Naruto and Sasuke also need time to precipitate, so they haven't left the village to practice.

"Naruto and Sasuke, we won't go out this vacation."

"Aren't you going out?" I have some regrets about not being able to get out of the village, and I can't go out to play.

"Hmm." Sasuke is very calm, and it doesn't matter if he can't get out of the village.

"Naruto, Sasuke, you can all develop your own ninjutsu, Spiral Pill and Chidori have great potential." Zhou Yu didn't tell Naruto, Sasuke Spiral Pill, and Chidori that the ninjutsu ideas developed in the follow-up were all developed after the two of them, and the strength is not weaker now than in the future, and there is no reason why it can't be developed now, what others tell and what they develop are completely two concepts.

Zhou Yu also began to expand the scope of the experiment.,Zhou Yu found that there were ninjas in the village around the experimental materials within the scope of the Fire Country.,It seems that some strange phenomena of the experiment have been discovered.,Now it's the early investigation.,If there's a danger, I'm afraid it will be erased.。

In order not to be exposed to Zhou Yu's ruthlessness, thirty-four shadow clones were dispatched overnight to erase all the experimental places, leaving no traces, and the traces erased Zhou Yu did not remove the shadow clones, and the shadow clones all retreated towards the country of wind, finding a top tank for themselves, diverting their attention, Zhou Yu's real destination was a small country in the ninja world, and the small country was the most suitable place for his experiment.

Thirty-four cottages disappeared overnight, and it really alarmed Konoha, many ninjas appeared in the disappearing cottages, and even two upper ninjas appeared, after all, the number of disappearing cottages was a bit too much, under the looming traces left by Zhou Yu, the ninjas of Konoha successfully found the border of the country of wind, and there were a lot of grievances between Konoha and Sand Hidden Village, dozens of them. The sand hidden village's ninjas appeared in the land of fire, and also eliminated thirty-four cottages overnight, among which there must be cats, of course Konoha can't be left alone, and ninjas are also sent to infiltrate the country of wind to investigate, Sand Hidden Village is innocent, and it was found that suddenly a Konoha ninja infiltrated the country of wind and naturally sent ninjas to infiltrate the country of fire to find out what kind of moth Konoha wanted, and the two sides sent ninjas to each other naturally caused a lot of friction, and also contributed to the Konoha destruction cooperation of the four generations of Kazekage and Orochimaru.