Well, usually in such a fanfic, a key plot point could be Naruto's discovery of some dark secrets in Konoha that make him feel betrayed. Maybe he finds out that the village elders were using him all along. Another plot point might be his transformation into this 'Dark Naruto' persona as a result of that betrayal. He could start to question his loyalty to Konoha and act in ways that oppose the village.
Naruto's character development is complex. He begins to see the world in shades of gray rather than the black - and - white view he had before. His sense of justice is warped. Instead of fighting for Konoha's version of justice, he starts to create his own. He may become more strategic and calculating, using his intelligence in a different way. His relationships change too. He no longer blindly trusts his friends, and this forces him to re - evaluate his identity. He is no longer just 'Naruto Uzumaki from Konoha' but something more complex and self - defined.
One possible reason could be fear. Naruto is extremely powerful, and some in Konoha might fear that he could one day lose control of his power. Another reason could be political intrigue. There may be certain factions within Konoha that see Naruto as a threat to their power and influence. Also, jealousy might play a part. Naruto has achieved so much and has the love of many, and some might be jealous and thus plot against him.
Naruto would likely be extremely hurt. He has always considered the Konoha 11 as his friends and comrades. So, at first, he would probably be in denial, trying to figure out what went wrong. He might try to talk to them, to understand their reasons.
One possible reason could be a misunderstanding. Maybe some false information was spread in the village that made Konoha believe Naruto had done something wrong. In fanfiction, things can be exaggerated and misinformation can easily lead to a situation of betrayal.
One possible plot could be that Naruto's incredible power makes the Konoha elders or some jealous shinobi feel threatened. They might spread false rumors about him being a danger, leading to the village turning against him. Maybe they frame him for a crime he didn't commit, like a powerful attack on the village that was actually the work of an enemy they secretly allied with. This would make Naruto, who has always been loyal to Konoha, feel extremely betrayed.
One possible reason could be jealousy. Naruto is very powerful and some in Konoha might be envious. For example, some minor clans might feel that Naruto, as an outsider in a sense, gets too much attention and resources. Another reason could be fear. His Nine - Tails power is so immense that some might fear he could lose control and endanger the village, so they betray him to try and eliminate the 'threat' before it's too late.
In these fanfictions, it might be related to the secrets Naruto holds. For example, if he discovers something about Konoha's dark past that certain people don't want exposed. They would then try to get rid of him by making him look like a traitor. Also, there could be external forces influencing Konoha to turn against Naruto, like other villages spreading false rumors.
One possible reason could be a sense of betrayal. Maybe he felt abandoned or mistreated by Konoha in some way. For example, if he was shunned because of the power within him that others feared.
Another way is through his attitude towards the villagers. He would show no respect or kindness to them. Instead, he would be cold and hostile, perhaps even going as far as to physically intimidate those who cross his path in Konoha.