In a fanfic where Naruto gets killed by Pain, it's a dark turn of events. The story would then likely focus on how the remaining characters cope. For example, Kakashi might feel a great sense of guilt for not being able to protect Naruto. Hinata would be heartbroken. Moreover, the Nine - Tails would be left without a host, which could also lead to all sorts of problems. The ninja world would lose its most prominent symbol of perseverance and friendship, and it would be a very different world from the one we know in the original Naruto story.
The story would change the whole dynamic of the ninja world. Naruto's friends would be devastated. They might seek revenge on his family, which could lead to a civil war within the village or among different ninja clans. Also, the enemies of the village might see this as an opportunity to attack, thinking the village is now weak without Naruto.
On a broader scale, Naruto's achievement as a Chunin could affect the relationships between the Hidden Leaf and other ninja villages. Other villages might view the Hidden Leaf as even more powerful or might be more cautious in their interactions with it. His new rank could also open up opportunities for diplomatic missions or alliances that weren't possible before.
A plot could revolve around the power vacuum left by Naruto. The Leaf Village is in disarray, and other villages start to make moves against it. Pain might realize that killing Naruto wasn't really what he wanted in the long run, as it led to more instability. Or maybe a character who was in the background in the original story steps up to try and fill Naruto's shoes. They struggle to gain the respect and power that Naruto had, while also dealing with the grief of his loss.
Well, in the Naruto fanfic universe, the idea of a 'Hashirama Heir' is quite significant. It can bring back the old glory and values that Hashirama represented. Fanfics may show the heir as a symbol of hope, inspiring other characters to be better. Also, it can create new storylines. For example, the heir might have to deal with enemies who want to use their connection to Hashirama for their own evil purposes. They would then have to protect their identity and the secrets of Hashirama's power.
The betrayal could lead to Naruto having trust issues not only with Sakura but also with others in the future. He might become more guarded and less likely to open up to people. For Sakura, if she comes to her senses later, she would have to face the enormity of what she has done. She would have to grovel for Naruto's forgiveness, but it would be a long and difficult road to regain his trust.
It can change the power dynamics. If Kakashi fails Naruto, Naruto may not reach his full potential as quickly or at all. This could mean that some of the battles in the Naruto universe are lost or are much more difficult. For example, against Pain or Madara, Naruto might not be strong enough without proper guidance from Kakashi.
It also affects the perception of other characters. For instance, the villagers might see Naruto in a different light if Kushina is openly blaming him. They could either side with Kushina, thinking she's right in her concerns, or they could support Naruto, seeing him as a victim of unfair blame. This can lead to new alliances or rivalries within the village.
Mentally, it would be a huge blow to the ninja community. Naruto inspired many with his never - give - up attitude. His death might make some ninjas lose faith in their own abilities and the future. But on the other hand, it could also fuel the determination of some to become stronger in his memory.
The impact would be huge. For one, all of Naruto's friends like Sasuke and Sakura would be devastated. Their whole world view which was centered around Naruto's positive influence would be shattered. Also, the village of Konoha would lose its greatest hope for the future. Naruto was seen as the one to bring about change and peace, so without him, the village might descend into chaos or be more vulnerable to outside threats.
It could have a major impact on the power balance. With Orochimaru gone, many of his secret experiments and knowledge could be lost or fall into the wrong hands. Naruto, being 'godlike', might be seen as the new power to keep in check. His friends and allies might start to distance themselves out of fear or respect for his new power level. The Akatsuki, too, would need to re - evaluate their plans as one of their potential allies or threats (depending on Orochimaru's relationship with them at the time) is no longer in the picture.