Definitely Naruto himself. He is the one Konoha wants back, after all. And then there would be his old friends like Sasuke. Sasuke might play an interesting role, either helping Konoha get Naruto back or being a bit hesitant because of his own complex relationship with Naruto. Also, characters like Iruka - sensei, who has always been like a father figure to Naruto, would be important. He could be the one who first realizes how much Konoha needs Naruto and starts the ball rolling to get him back.
Obviously Naruto would be one of the main characters as the story is about getting him back. Sakura could also be a main character. She might be one of the ones leading the effort to bring Naruto back, using her medical skills and her friendship with Naruto as reasons to convince him.
In a 'konoha wants naruto back fanfic', perhaps there's a prophecy that says only Naruto can save Konoha from an impending doom. The villagers, who once shunned Naruto, now understand his importance. They start a campaign to bring him back. Tsunade could be leading this effort, offering Naruto things like a proper apology for how he was treated in the past and a high - ranking position in the village.
The antagonist could be a new, self - proclaimed ninja god who wants to rule over all the villages. He sees Naruto as the only threat to his power, so he used a powerful spell to take away Naruto's godlike abilities. Konoha wants Naruto back to stop this tyrant. This antagonist might have an army of brainwashed ninja at his command.
I think Naruto is the central character. His friends, such as Kakashi, who was his teacher, would also be main characters. They would be involved in Naruto's journey of dealing with being labeled as a demon in Konoha. Additionally, any villains or antagonists who oppose Naruto because of his 'demon' status could be main characters. For example, if there are some villagers who are against Naruto and try to drive him out, they could be considered main characters in the context of this fanfic.
The main characters are, of course, the Konoha Twelve. This includes Naruto Uzumaki, Sasuke Uchiha, Sakura Haruno, and others. They are the focus of the fanfic and usually the ones driving the story forward with their actions and decisions.
Another main character could be Kakashi. As Naruto's former teacher, he might be conflicted about Naruto's exile. He could be trying to find a way to bring Naruto back to Konoha or at least help him in some way while also having to deal with the village's decision. And of course, there could be new characters introduced specifically for this fanfic, like a mysterious figure who helps Naruto during his exile.
The main characters would most likely start with Naruto. His character would be central to the story. Alongside him, we might see the Hokage at the time also playing a role. Additionally, there could be a group of shinobi who are specialized in dealing with demons that Naruto teams up with. And perhaps some of the villains or demons themselves could be considered main characters in a sense, as they drive the conflict in the story.
Sakura could be one of the main characters. She has a long - standing relationship with Naruto and might play a role in convincing him to return. Maybe she tells him about the state of the village's hospital or how his friends miss him.
It could be a rogue ninja from within Konoha who doesn't want Naruto to return because he fears Naruto's growing power will disrupt his own plans for power within the village.
Naruto would probably be conflicted. On one hand, he has a deep love for Konoha, his home. But on the other hand, he might have been hurt by the past events that led to his departure. He could initially be hesitant, but eventually be swayed by the thought of seeing his friends again.