In such a fanfiction, they might leave Konoha to start a new life in a peaceful place. Maybe they are tired of the shinobi life full of battles and politics in Konoha. They could find a small village by the sea and build a simple house there, living a quiet life away from the chaos.
Hinata would be heartbroken at first. Naruto is someone she deeply cares about. But she's also a strong - willed ninja. So she might start by trying to understand why Naruto left. She could look for clues in the village or talk to Naruto's friends to figure out his possible destination.
Konoha would initially be in shock. Naruto is a hero to many in the village, and his sudden departure with Itachi, who was once considered a traitor, would cause a lot of unrest. The villagers might start to question the leadership of the village, wondering why Naruto left and if there was something they could have done to prevent it.
Another reason could be that he witnesses corruption or unfairness within the village leadership. If he sees that the system is rigged against certain groups, including himself or his friends, he could grow to hate Konoha and decide to leave.
One possible reason could be to seek stronger opponents outside of Konoha. Naruto might feel that he has outgrown the training opportunities in the village and wants to face greater challenges.
This type of fanfiction concept is really out of the ordinary. Naruto's character is built on his values of friendship, loyalty, and his dream of becoming Hokage. Killing Sasuke would mean betraying all of that. However, in a fanfiction, the author might be exploring the 'what - if' scenario. For example, what if Sasuke's actions against Konoha were so heinous that Naruto felt he had no choice? But still, it's a far - fetched and very different view from the original Naruto we know.
It would be a huge blow to Konoha. Naruto is a hero in the village, and his departure would leave a big leadership void. The villagers would also lose a great source of inspiration. Hinata is from a respected clan, and her leaving would also have an impact on the clan's standing in the village. Morale among the ninjas might drop as they see two important figures leave.
They could leave because of a prophecy. Some ancient prophecy might state that they need to leave Konoha to fulfill a greater destiny elsewhere. So they trust in this prophecy and leave their home.
It could lead to political unrest in Konoha. There might be those who blame the village leadership for Naruto's departure. This could lead to power struggles as different factions try to take control and change the way the village is run. Some might demand more transparency and better treatment of their shinobi to prevent such a thing from happening again.
Konoha's power structure could be affected. Naruto is one of the strongest shinobi in the village. Without him, the village might be more vulnerable to attacks from other villages or threats. They would need to quickly find ways to fill the gap in their defenses.