Well, Naruto is almost always one of the main characters. Since it's Naruto - themed fanfiction. And of course, the mad chemist is another main character. They could be a new character created specifically for the fanfiction, or it could be an existing character from the Naruto universe who has taken on the role of a mad chemist, like Orochimaru perhaps.
Another possible main character could be a character who is affected by the mad chemist's experiments. For example, if the chemist creates a new type of jutsu that goes wrong and affects a civilian or a minor ninja character. That character then becomes central to the story as Naruto and the others try to fix the situation caused by the chemist's actions.
Often, Naruto's friends like Sakura and Sasuke might also be important characters in 'mad chemist Naruto fanfiction'. Sakura might be intrigued by the chemist's work and try to learn from them, while Sasuke could be suspicious and see the chemist as a threat. Their interactions with the chemist and Naruto can drive the plot forward in different ways.
Obviously, Naruto is the central character as the title 'naruto goes mad' implies. Sasuke often plays a crucial role too. He might be the cause of Naruto's madness in some cases, like if he betrays Naruto again in a more extreme way. Sakura could also be involved, perhaps trying to bring Naruto back from his madness. And Kakashi, as Naruto's former teacher, may try to figure out what's wrong with Naruto and find a way to help him.
One interesting 'mad chemist Naruto fanfiction' could be where the mad chemist discovers a new jutsu formula that gives Naruto some unique power. Maybe it's a potion that enhances his chakra in a strange way.
Well, obviously the mad doctor is a main character. He could be an original character created specifically for the fanfiction. Then there could be Naruto himself, who might be involved in trying to stop the mad doctor's evil plans or, in some cases, might be seeking the doctor's help for a friend's illness.
As I don't know the exact 'al chemist novel', it's hard to say. But often, there would be an alchemist as a main character, perhaps a young and ambitious one.
The main characters are often Naruto, as he is the focus of the mecha concept. Shikamaru could also be a main character in this type of fanfiction. He would be the strategist, trying to figure out how to best utilize the mecha Naruto in battles. Additionally, Orochimaru might be a character in some cases. He could be interested in stealing the technology of the mecha for his own evil purposes or trying to manipulate Naruto through it.
Obviously, Naruto and Matsuri are main characters. Naruto, with his energetic and determined personality, often drives the story forward. Matsuri, being from Suna, brings a different perspective to the story. Sometimes, other characters like Sakura or Kakashi might also make an appearance to add more depth to the plot.
Obviously, Naruto is the main character since it's in the title 'naruto is hokage fanfiction'. But other important characters usually include his friends like Sasuke, Sakura, and Kakashi. They might play different roles, like Sasuke could be Naruto's advisor or a special agent for the village.
Well, Naruto himself is obviously a main character as it's about his time as the 7th Hokage. His family, like Hinata and his kids, often play important roles too. Boruto, his son, might be a central figure as he is growing up in the shadow of his father and has his own journey to become a strong ninja.
In most 'Joker Naruto' fanfiction, Naruto is always there as the hero trying to protect his village and his way of life from the Joker's antics. The Joker is the main source of trouble. But characters like Sakura can also be important. She might use her medical ninjutsu to heal the victims of the Joker's chaos. And then there are the Hidden Leaf Village elders. They would be worried about the impact of the Joker on their village and might try to make decisions on how to handle the situation, making them significant characters in these stories as well.
Well, obviously Hanabi and Naruto are the main characters in most of these fanfictions. Hanabi, as a member of the Hyuga clan, brings her own set of skills and family - related storylines. Naruto, with his dream of becoming Hokage and his unique abilities, often interacts with Hanabi in different ways, like helping her overcome her clan - related issues or going on adventures together.