Reicarnated as a Hyuga in the Warring States Period

The next few days, Madara and Hashirama met and, while rekindling their friendship, they discussed the details of the foundation of the village.

Then, the Uchiha and Senju and all their affiliated clans met. Under everyone's gazes, Hashirama and Madara shook hands and declared the establishment of Konohagakure.

Hijiri immediately expressed the intention of the Hyuga clan to join.

Soon other clans like the Sarutobi, Shimura, Ino-Shika-Cho alliance, Inuzuka, Aburame, and Kurama clans. Hijiri also invited the Hatake and other samurai clans he found trustworthy.

While Hashirama wanted to put Madara in the position of Hokage, everyone else, except for Izuna and a few Uchiha, disagreed. Then under the pressure of the Daimyo, he was elected the first Hokage of Konoha.

Everything proceeded smoothly from then on: Hashirama with his impressive Wood Release built the infrastructure of the village and Hijiri used his clan's accumulated wealth to speed up the expansion of the village while attracting merchants.

During this time Hashirama approached Hijiri.

(Hashirama): "Hijiri, I wanted to ask you something."

(Hijiri): "Speak freely, Big Brother. Are there some problems I can help you with?"

(Hashirama): "Yes and no. Right now everything is progressing in the right direction. But Tobirama told me that the work has only started and he wanted your help to deal with it."

(Hijiri): "I would be honored. But why me?"

(Hashirama): "Well I first thought about Madara, but he isn't really suited for desk jobs. So I take it is a yes?"

(Hijiri): "Yes, of course, count me in"

(Hashirama): "Hahaha. Good from now on you will be the first Hokage's advisor."

Hashirama and Hijiri shook hands. The title of advisor, which wouldn't have appeared before the ascent of the Third Hokage, was given now to Hijiri.

A few days later Izuna left the village to travel on his own. Since the rules of the village had yet to be created and Izuna was the Vice Leader of the Uchiha clan, he wasn't branded as a traitor. 

A year passed the village thrived and started to take missions from the surrounding villages, merchants, and the various Daimyos. More and more teams composed of ninjas of different clans were formed. This was to promote unity in the village and to diversify the skills of every team.

Hijiri spent his time from paperwork to perfecting his latest techniques. One was an enhancing and defensive technique, the other was a life-extending technique. He was already 25 and he had almost reached the peak of his strength. But his aim was higher: he wanted to continue to improve, and that wasn't happening if his strength started declining.

The model of Konoha village inspired the clans of the other big Lands. They banded together and established themselves with hidden villages and Kages. The warring states era had officially ended.