It has been some years already since Kira awoke in this world.
In these years, he started to train himself and Naruto in the ways that suited a pair of kids.
Chakra control and combat awareness, he also started to learn one of the most cheat-like abilities that anybody that saw the anime would want, the Shadow Clone Jutsu.
A regular kid wouldn't be suitable to use a Jutsu that divides the chakra pool of the user, the technique is after all designed for Jōnin level ninjas. Even with his big Chakra reserves, Kira was able to practice the Jutsu only because he has half the Kyūbi inside him. Which is also another cheat-like existence with nearly infinite Chakra.
One thing that he discovered by accident, is that he 'absorbed' The Chakra of a tree when he rested against it after depleting his reserves practicing.
This leads to Kira suspecting that he has a special bloodline.
The training that he did was always away from prying eyes. The outskirts of the Forest of Death became the best training grounds.
Although the Hokage had some ANBU's 'watching over' the kids, it was obvious that they didn't have the level to do it. Hell, in the anime Naruto without any control of Chakra was always able to hide from them as a little kid. It speaks of the level that they possess.
In the first-year, important things that happened where.
Following the 'canon history' Naruto saved Hinata from some Bullies.
The difference with the 'canon' is that this Naruto has a year to train, so he was able to easily defeat the small gang of kids.
The problem was that he grew cocky with the victory and nearly lost when they attacked him again, although in the end, he won, he learned his lesson of 'defeating the enemy till they can't poss a treat anymore'.
This was also the time when Kira started to train in the Shadow Clone Jutsu and discovered the abnormality of his body. He decided to wait until an important event so he can get a very big benefit thanks to his ability.
The second-year important events could be compared to the first one, just that this time it was Kira who after a day of training with Shadow Clones in Chakra control, and leaving Naruto training. Came across a group of kids ganging on a little blond girl.
He decided to go near the act and heard how they were the typical problem boys whose fathers were in prison because of the father of the little girl. So they decided to Bully her.
Feeling their Chakra pool he concluded that they were nearly Mid-level Genins.
Although he was training these past years, in the end, he was just a kid,
also, he didn't want to attract attention because a 'five-year-old civilian' could beat a pair of ninjas.
In the end, he managed to use the environment to his advantage, as the group of Genins didn't want to attract attention they cornered the little girl in a desolated alleyway, as some modifications were going to the buildings, Kira managed to break a support bridge of wood by launching a Chakra coated stone. This caused the debris and some materials to fall where the gang was.
Kira took the opportunity and holding the hand of the little girl he carried her away.
He hid her in an empty container and then using stones to mislead the pursuers until he finally lost them. After all, they were just normal cannon fodder that couldn't match him in certain areas.
Afterward, he took the girl out of the container, when she finally found herself in a safe environment, she hugged Kira and started crying in his chest while thanking him. Kira then learned that he helped the young Ino Yamanaka.
While walking Ino to her home, Kira started talking with her, and before leaving, advised that it would be better if she trained so that this wouldn't happen again.
After Ino talked about this event to her father that group of ninjas just disappeared.
Thanks to this incident where Kira had to think about how not to get exposed, he decided to train in the Henge no Jutsu (Transformation Technique), as it was only an E-Rank Jutsu, as Kira has been practicing Chakra control, he mastered the Jutsu in just a little over two months.
Thanks to the Henge no Jutsu Kira was able to enter the public Library so that he could start recollecting information.
By the end of the year, his mastery of the Jutsu reached the point of not requiring Hand-seals and not letting out a cloud of smoke. He also taught this technique to Naruto after his training with tree-walking.
After some training with Naruto, Kira came to understand that the two halves of the Kyūbi gave them different advantages.
The yang part of Naruto gave him a greater physical condition, which will help him as he intends to be a close-quarters ninja.
The yin part, instead gives a better Chakra control, bosting Kira Genjutsu, and Ninjutsu.
As there exist things like the Rinnegan that can absorb Chakra, Kira thought that it would be a wise move to also train his body and Taijutsu.
Thanks to this he started to train with weights, he got them by stealing some ryu from the people who wished the dead of the 'Demons'.
With that income Kira was able to eat more than just Ramen, to the sadness of Naruto, he could only explain to him that a balanced diet is helpful for the body and that they could still eat Ramen at weekends.
Something that happened afterward was the messengers of Iwagakure coming to the village for peace talks. This should be the time were Hinata is kidnapped by the messengers of Iwa so Kira thought that the future was changing.
He just let the things follow as they should, with Hinata being saved and her uncle having to sacrifice himself for his brother to Iwa.
The third-year Kira and Naruto started training with water-walking, and while Kira would have liked to start training Taijutsu, he wasn't able to enter the library where Jutsus are recorded, as there is more than one way he could get spotted trying to enter he choose not to act rashly.
The best he could get where some D-Rank Jutsus when he got the opportunity.
He managed to obtain four Jutsus
Wind release- Zephyr
Fire release- Fire Style Strike
Water release- Water Trumpet
Water release- Dark Fog
Afterward, Kira taught the Water Trumpet to Naruto, he thought that if Hashirama was capable of using the wood release while being the reincarnation of Ashura, then, shouldn't Naruto be able too?.
He decided to help Naruto awaken Ashura Chakra in the future as he was too weak for it right now.
Now Kira was just waiting for a very important event that will help him.