It could be an old - fashioned village elder who has always been against Naruto. They might see him as a threat to the traditional way of life in the village and so start spreading rumors that lead to the villagers turning on him.
One possible plotline could be that the villagers, out of long - held fear and jealousy of Naruto's growing power, band together in a mob. They might ambush Naruto when he is least expecting it, perhaps on his way back from a mission. Another could be that they are influenced by a powerful and evil - minded individual who manipulates them into believing Naruto is a threat to their safety.
One possible reason could be fear. Naruto has the Nine - Tails inside him, and the villagers might be so afraid of the power of the Nine - Tails getting out of control that they decide to take extreme measures. They might see Naruto not as a person but as a potential threat that needs to be eliminated.
One possible reason could be the way the villagers treated him as a child. They ostracized him because he was the host of the Nine - Tails. He was often alone and looked at with fear and disdain, which could have gradually built up his hatred.
Hinata would be devastated. She has always had deep feelings for Naruto. She might lose all hope and become a shell of her former self. Also, Kakashi would feel a great sense of guilt. He was Naruto's teacher and protector in a way. He would probably question his own abilities and actions that led to this situation. And for the village as a whole, it would soon realize the mistake they made when they face new threats without Naruto to protect them.
Well, one way could be that the villagers' long - hidden fear and jealousy of Naruto's power finally boil over. Maybe they believe some false rumors that Naruto is about to destroy the village. So, in a fit of panic, they turn on him all at once and overpower him.
One reason could be years of built - up resentment. The villagers have treated Naruto poorly for so long, constantly shunning him and making him feel like an outcast. In fanfiction, this could reach a boiling point where he just snaps. For example, if someone in the village made a particularly cruel comment about his parents, it might be the last straw.
It could also be a situation where Naruto is framed for a crime he didn't commit by someone in the village. As a result, the villagers turn on him even more, and in his self - defense and anger, he ends up fighting back and killing some of them.
Naruto would probably start by recruiting his friends and their families. He knows them well and trusts them, and they share his values. He could also offer a new start to people who have been ostracized from other villages. His reputation as a hero would attract many who are looking for a better place to live.
Naruto might react with confusion at first. He has always wanted to be accepted by the villagers, so being attacked is the opposite of what he expected.