Naruto himself could be a main character as the fanfic might explore how his life could have been different without the Sandaime's influence. Another likely main character could be Orochimaru, especially if the fanfic focuses on the Sandaime's failure to deal with him properly.
The main characters could be those who were directly or indirectly affected by the Sandaime's decisions. For instance, Sasuke might be a main character if the fanfic delves into the Uchiha massacre and the Sandaime's role in it. Itachi could also be a central figure as his actions were closely related to the Sandaime's decisions regarding the Uchiha clan.
Well, characters who had a rough start in the village due to Sandaime's decisions might be likely to support the bashing. For example, Naruto himself could be one. Given his difficult childhood with little support from the village at first, which some might blame on Sandaime, he could be portrayed as having negative feelings towards him in these fanfictions.
From the Tsukune side, Tsukune would be there as the character being bashed. His friends from his own story might also make an appearance, but mainly to be overshadowed by the Naruto characters. For example, Moka could be in it, but the focus would be on how Naruto characters are better in various aspects compared to her and Tsukune.
One common theme could be criticizing the decisions made by the Sandaime Hokage. For example, his handling of the Uchiha situation might be a point of contention in such fanfics. Another theme could be exploring how the village would have developed differently if he hadn't been in power or had made different choices.
Well, obviously Percy Jackson and Jason are the main ones. Given that it's a bashing fanfic, they will be at the center of the story. Their actions, personalities, and relationships will be the focus.
In 'naruto sandaime bashing fanfiction', a frequent theme is his political decisions. His choices in maintaining the power structure within the village can be a target. For instance, some might write that he was too lenient with the powerful clans, which led to an imbalance. And his actions during the various ninja wars might also be criticized, like his military strategies or his decision - making processes that might have cost many shinobi their lives.
Well, obviously Naruto himself would be the main character. There could also be his friends like Sasuke and Sakura, who might be involved in the interactions between the two Narutos. Maybe they are confused at first by seeing two Narutos, but then they help them figure out what's going on.
It could still be Naruto himself. Since he's the central character in the original series, many fanfics would likely continue to build on his story.
Definitely Naruto. His whole life was full of suffering because of the Leaf Village's treatment of him as a jinchuriki. Sakura could also be involved. In some fanfictions, her growth might be stunted by the village's lack of proper support or opportunities for female ninjas. And Kakashi. His past traumas related to the village, like the loss of his teammates, could be used as a way to criticize the village's way of handling missions and the safety of its ninjas.
Obviously, Naruto would be one of the main characters as the story is about him being the son of Whitebeard. Whitebeard himself would also be a major character, even if he might not be around for the whole story. And then there would be the other members of the Whitebeard pirates, like Marco. They would play important roles in Naruto's life in the pirate world, either as mentors or comrades.
Obviously, Naruto and Jiraiya are the main characters. They are the focus of the 'naruto meets jiraiya' concept. Naruto, the energetic and determined ninja, and Jiraiya, the wise and powerful mentor.