Obviously Naruto himself is the central character. Sasuke would also likely be involved. Given their history and Sasuke's own complex relationship with Konoha, he might side with Naruto or at least be a key figure in the events. Kakashi too, as he has been Naruto's teacher and is an important figure in Konoha. He could be caught in the middle, trying to understand Naruto's motives and also trying to uphold Konoha's stability.
The village elders like Danzo would be important characters. If Naruto is turning on Konoha because of some corruption or unjust actions, Danzo might be at the center of it. Hinata could also be involved. She has deep feelings for Naruto and would be affected by his actions. She might try to talk to Naruto and understand his reasons, or she could get involved in the conflict in some way to protect Naruto or Konoha.
Other characters like Shikamaru, who is known for his intelligence, could play a role. He might be the one trying to figure out Naruto's plans and come up with counter - strategies for Konoha. And Rock Lee, with his unwavering loyalty to Konoha, could be in direct opposition to Naruto at first, but later come to understand his point of view as the story unfolds.
The village elders are very likely to be involved. They often have a say in the big decisions in Konoha. They might be the ones who decide that Naruto must return for the safety or the benefit of the village. Tsunade could also be a part of it. If she's still in charge, she might be in a difficult position of having to order Naruto back or deal with the consequences of his forced return.
Sasuke would likely be involved. He has his own issues with Konoha and might side with Naruto, either out of friendship or his own vendetta against the village. Also, the elders of Konoha like Danzo could be important characters as they might be the ones behind Naruto's banishment.
Obviously, Naruto would be the main character as it's about his revenge on Konoha. Sasuke could also play a significant role. He has his own issues with the village, and he might either support Naruto's revenge or try to stop him depending on how his character is developed in the fanfic. Sakura might be there too. She could be caught in the middle, trying to figure out whether to side with Naruto or stay loyal to Konoha. And Kakashi, as Naruto's former teacher, would likely be involved. He might be one of the people Naruto has to face if he's set on his revenge, or he could be trying to reason with Naruto.
Well, in the 'naruto trains and returns to konoha fanfic', Naruto is the central figure. For his training, he could meet some new characters who are experts in certain ninja arts. But in Konoha, all his old comrades will be there. Shikamaru, who is known for his intelligence, might be involved in planning something related to Naruto's return. Ino could be there too, perhaps using her mind - related jutsus to help in some way. And of course, the old sages or elders of Konoha would also be present to assess Naruto's growth and the impact of his return on the village.
In the 'yugi turns into a girl fanfiction', apart from Yugi's main group of friends, there could be some new characters introduced. Maybe a mysterious figure who knows the secret behind the transformation and can either help or hinder Yugi. Also, Yugi's grandfather might play an important role. He could be worried about his grandson/granddaughter and try to find a solution to reverse the transformation. And of course, the spirit of the Millennium Puzzle, Yami Yugi, would also be involved, perhaps having a different kind of connection with Yugi in this new form.
Naruto is the obvious one. His connection to the Uzumaki clan makes him the driving force behind the rebuilding. Hinata would also be likely involved, as Naruto's wife, she would support him and might contribute to the new Uzushiogakure in areas like family support and community building.
Definitely Hinata. Her gentle yet strong - willed nature could be an interesting contrast when dealing with the often - mischievous yokai from Nurarihyon. Gaara too, as his own experiences with being an outcast and having a powerful force within him could have parallels in the Nurarihyon world where some yokai are feared or misunderstood. And Rock Lee, his determination and unique fighting style could bring a new dynamic to the interactions in the fanfic.
Obviously, Naruto is the central character. But other characters like Sasuke could also be involved. Sasuke might be torn between his loyalty to Konoha and his friendship with Naruto. He could either try to bring Naruto back or join him in his exile.
Sasuke is a very likely character. He already has a strong connection to hate in the original series due to his clan's massacre. In a fanfic about the power of hate, his journey could be further explored, like how he might be tempted by even darker forms of hate - driven power. Another one is Obito. His fall into darkness was also driven by hate, and in a fanfic, his character could be used to show the extreme lengths that the power of hate can take someone.
In a 'naruto finally snaps fanfic', Naruto is the main focus, but characters like Kakashi would be involved. Kakashi has been Naruto's teacher and mentor, so he would be affected by Naruto's change. Also, characters from other villages such as Gaara could be part of the story. Gaara has his own connection with Naruto, and Naruto's snapping would have an impact on their relationship and the balance between villages.