Rebirth in the Naruto World

It had been four years since Itachi and Ren were born, but the Third Shinobi World War was waged and Itachi and Ren both witnessed first-hand many casualties as a result of the Third Shinobi World War. Traumatising Itachi, which led to him having a dream of erasing fighting from the world. Of course, this dream led to him training much more than he previously did. While Ren decided to increase the intensity of his training as he realized Itachi was also growing much faster than him.

...

A year later, there was a familiar scene with an intense atmosphere as Itachi and Ren were outside the hospital room waiting for permission to enter. Inside the room was Mikoto who was holding Fugaku's hand, who was right next to her.

"It's out! It's a healthy boy!" exclaimed the midwife, while holding a baby.

"Can I hold him?" asked Mikoto exhausted.

"Sure, by the way, what's his name going to be?" the midwife responded.

"We decided to name him Sasuke," Mikoto responded happily at the sight of her son, then she continued "Honey go let the boys in to see their little brother."

Fugaku hurriedly left the room and came back ten seconds later with two, five-year-old boys. These two were Itachi and Ren, who excitedly rushed up to their newborn little brother.

"Mom, can we hold them?" Ren asked excitedly.

Mikoto responded happily at the sight of her two children, "Sure" as she gave Sasuke to Ren and Itachi to carry.

Fugaku then solemnly said, "As you two are his older brothers, you will need to take care of him in the future".

Both Ren and Itachi responded with a "Yes Sir!" as they continued to hold Sasuke.

...

Standing at the Uchiha lake were Itachi and Fugaku.

"Itachi, I'm going to teach you the Uchiha's Fireball Jutsu," Fugaku told Itachi.

Under the excited gaze of Itachi, Fugaku formed multiple hand signs at a slow speed so Itachi could see, then blew a huge fireball over the lake.

"Listen Itachi the hand seals are-" Fugaku was interrupted when Itachi immediately copied Fugaku's hand seals and blew a fireball equal to the size of Fugaku's.

"Father I did it!" Itachi said excitedly.

"That's my boy," Fugaku said while smiling.

While Itachi was learning Ninjutsu with Fugaku, Ren was in the back of the woods also practicing Jutsu. He formed multiple hand signs at a very quick pace, then suddenly grabbed his right arm with his left, when a coat of lightning surrounded his hand. In an instant he suddenly charged towards the side of a cliff and thrusted his hand through, completely piercing the wall making a hand-sized hole in the wall.

"I finally learned Chidori after a month", Ren thought. "But the fact that Sasuke learned it only after a week shows how talented he is, but for me with no talent, I have to put in several times the amount of effort to catch up to everyone".

...

It was late a night when Itachi and Ren were at home playing with Sasuke when they suddenly hear a loud-

"BOOM"

Running out of their house to the sounds of destruction and screams Ren and Itachi suddenly feel an immense and terrifying Chakra. It was the Nine-Tailed Demon Fox, Kurama.