Naruto: Rebirth Of The Seventh Hokage

Years of wars with the foreign invaders turned the shinobi world into one united entity. Humanity grouped together as one to fight the same enemy.

Past enmities were forgotten, every hidden villages shared their resources and there was no discrimination between country, races, or clans. Everyone is a part of the shinobi alliance and their sole duty is to fight the foreign invaders and protect their homeland

During the war, almost all ninja techniques from every part of the world were collected and shared among the shinobi alliance with only one objective in mind.

Get stronger together!

Forbidden techniques, hidden art, kekkei genkai, and pretty much every ninja techniques in existence are accessible to every shinobi in the alliance, proving how desperate the situation was at that time.

During the fourth shinobi war, a ninja would just learn a couple of ninja techniques and only focused on training those techniques for their whole life. It's better to just master one technique and be good at it rather than learning everything but sucks at it.

For example, Naruto dominated the war with only his 'Rasengan', 'Shadow clone' and 'Kurama cloak' techniques while Sasuke only depends on his 'Chidori' and 'Sharingan' during his fight.

Even the copy ninja Kakashi that was famous for copying thousands of ninja techniques would most of the time only use his 'Raikiri' and 'Kamui' during his fight.

However, the arrival of those foreign invaders changes everything. Their body was coated with a metallic armor sheets that was designed to develop immunity to any chakra based ninjutsu the longer it was exposed to it.

The more prolonged the fight, the less effective the technique would be. Unless you can kill the invaders in one hit, it's better to just retreat before the foreign invaders could fully develop their immunity to your ninja techniques.

Because of this problem, more and more shinobi started learning multiple variety of ninjutsu just to increase their options during the fight.

Twenty years later, the sight of a Kumogakure ninja using the Nara clan 'Shadow bind' technique or seeing a jounin from Konoha using the Sunagakure puppet technique during a fight will become a norm.

During his time as the seventh Hokage, Naruto established a Ninjutsu Research Institute near the border of Konoha to gather every ninja techniques possible that have existed in the world.

He then instructed the research team to start working on improving and researching all those techniques. All of this efforts were done to increase the alliance army fighting prowess.

.......

"SHADOW CLONE KAI!"

'Poof! Poof! Poof!"

Naruto created three identical clones of himself. Currently he is training in the outskirt of the village, a few miles from a stream where the valley of the end is situated.

"Tsk, I've been skipping the academy class for a week now. Iruka sensei would be soo pissed at me."

"You, go back to the village and join the class for me. If anything happened, just dispel yourself to let me know the situation." Naruto instructed one of his clones.

The clone nodded in confirmation before disappearing using the shunshin technique.

'Shadow Clone Kai' is an improved version of the 'Shadow Clone' technique developed by the second Hokage.

Years of extensive research and by comparing the jutsu to countless other variety of clone ninjutsu from all around the world, the bright minded geniuses in the research institute finally formulated this technique.

The information rush after the clone was dispelled are also mellowed down and would not inflict any damage to the brain nerves cells.

And the best part about the technique is the toughness of the clone. The clone would never get dispelled unless it was attacked by a jutsu with at least rank A in level, making the battle prowess of each clone almost on par of the original.

Naruto dominated the battlefield and killed millions of foreign invaders by himself during the war thanks to this ninjutsu. It was one of the reasons why the foreign invaders were deeply frightened when they heard his name.

"I only have limited time before I'm being promoted into a genin and what I need to do the most right now is to solidify my foundation." Naruto thought to himself.

"My body condition is currently trash level with all the instant ramen I've been eating all these years. Luckily I am an Uzumaki with enourmous amout of vitality or else I would get sick or even die with all these artificial stuff and chemicals accumulating inside my body." Naruto thought to himself.

"Your task is to be in charge of food. You will hunt for wild animal and collect some wild fruits and vegetables for us to eat during training. It is time for us to start eating healthy and fulfill one of our mother's wish." Naruto said to another one of his clone with a bit of melancholy in his voice.

"Understood". The clone then shunshined away.

"Now I can focus on my training. Hmm. To solidify my foundation, the first thing I need to do is to improve my body constitution to the limit in the fastest time possible. There's only one technique that I can think of. And that technique would definitely shock the world if it was exposed in the current age." Naruto chuckled.