Obviously Naruto himself is a main character. Since it's about his inner hollow, he is at the center of it. Sakura might also be involved as she is one of Naruto's closest friends. She could be the one to notice the changes in Naruto due to the inner hollow and try to help him.
Naruto is the primary character, no doubt. But Sasuke could also play a significant role. He and Naruto have a complex relationship. In the context of the inner hollow fanfiction, Sasuke might sense something different about Naruto and either be a rival in a new way or an unexpected ally. Additionally, Kakashi could be involved as Naruto's mentor, guiding him through the discovery and dealing with the inner hollow.
The main character is Naruto, of course. However, other characters like Jiraiya could be important. Jiraiya has trained Naruto and has a deep understanding of his character. In a story about Naruto's inner hollow, Jiraiya might use his knowledge and experience to help Naruto understand and control this new aspect of himself. And Hinata, who has feelings for Naruto, could also be part of the story, perhaps being a source of emotional support for Naruto during his struggle with the inner hollow.
Often, the main characters are Naruto and his friends. Naruto, as the protagonist, is naturally drawn to the mystery of the egg. His friends like Shikamaru, who is intelligent and can strategize about how to deal with the situation regarding the egg, and Choji, who might provide some physical protection if needed. Hinata could also be involved, perhaps having a special connection to the egg because of her Byakugan. And then there are the villains, like the members of the Sound Five, who might want to get their hands on the egg for their own evil purposes.
Naruto himself is almost always involved as he is the main character of the Naruto series. His friends like Sasuke and Sakura may also be part of the story. Sometimes, even villains like Orochimaru or Madara could be involved if the plot of the fanfiction is related to a big threat where their knowledge or power is needed.
Obviously, Naruto himself is the central character as it's about him 'snapping'. Sasuke is also often involved. He might be a factor in what causes Naruto to snap, or he could be on the receiving end if Naruto's snapping is directed at his actions or decisions.
In 'naruto angry fanfiction', characters like Hinata can also be involved. If she is in danger or if Naruto feels that he couldn't protect her well enough, it can stir his anger. And villains like Orochimaru or Madara can be present as they are often the source of problems that make Naruto angry, whether it's through attacking the village or harming his friends.
Obviously Naruto is the main character as he is the one usually pulling the pranks. His friends like Shikamaru might also be involved, either as victims of the pranks or as accomplices. Sakura could be in there too, perhaps getting annoyed at Naruto's pranks or being part of a prank on someone else.
Obviously Naruto is the main character. And sometimes his parents might be involved in a more complex way, like through flashbacks or alternate storylines where they had reasons for the so - called 'abandonment'.
Obviously Naruto himself is the central character as it's about his lifeless eyes. Sakura could also be involved as she is one of Naruto's closest friends. She might be the one to notice the change in his eyes first and try to help him.
Obviously, Naruto himself is the central character. But other characters like Sakura might also be involved. She could be the one trying to get Naruto sober or scolding him for his drunken behavior.
Obviously Naruto himself is the central character as the story is about him cutting himself. Sakura is often involved as well. She is Naruto's friend and a medical ninja. So she might be the one to discover Naruto's self - harm and try to heal him both physically and mentally.
Sometimes Naruto can also be a main character in these fanfictions. He might be the one who notices the neglect of Sasuke's Sharingan and tries to help him in some way. Their friendship could be explored in a new light, with Naruto being more proactive in understanding and supporting Sasuke's power.