The main characters would surely be Naruto and the troll emperor. But it's possible that the fanfic could introduce a new character, like an assistant to the troll emperor who is just as wacky as their boss. This character could add more layers of humor to the interview. Another character that could be involved is Hinata. She might be in the background, blushing and cheering for Naruto from afar during the interview. And of course, Kurama, Naruto's inner beast, could have some sort of influence on how Naruto responds to the troll emperor's wild antics, even if he doesn't physically appear in the interview.
Well, aside from Naruto and the troll emperor, I think Sasuke could also make an appearance. He might show up to either support Naruto or to be annoyed by the whole situation. And there could be a cameo from Jiraiya. He might be there to add some wisdom to the crazy interview scenario, maybe trying to give Naruto some advice on how to handle the troll emperor. Also, the interview might be held in a place where other minor characters from the Naruto world are around, and their reactions could be part of the story too.
Well, it could be full of unexpected and humorous interactions. Maybe the troll emperor would say really outlandish things during the interview that would make Naruto fans laugh.
Obviously Naruto would be one of the main characters as the title implies he's the emperor. Another could be Sasuke. He might be Naruto's right - hand man or sometimes a rival within the new empire. From the Avatar world, Aang could be a major character. He could either be an ally or someone who initially doubts Naruto's rule but later comes to respect him.
The title 'harry bribes the troll fanfic' clearly indicates that Harry is a main character. He is the one taking the action of bribing. The troll is another main character as it is the recipient of the bribe. However, in the context of the Harry Potter universe, there could be other characters that play important roles. For example, Hermione might be there to offer advice to Harry about whether bribing the troll is a good idea or not. Ron could also be involved, perhaps he is initially against the idea but later comes around. So, while Harry and the troll are the obvious main characters, there may be others depending on how the fanfic is written.
It could be the person or group who sent the troll. Maybe there's a mastermind behind the troll's actions, like a villain who wants to distract Bucky from something important. So while the troll is the immediate target of Bucky's punch, the real enemy is the one pulling the strings.
The Akatsuki could still be a major antagonist. Even if Naruto is emperor, they might oppose his rule as it goes against their own goals of chaos and obtaining the tailed beasts.
In this fanfic, Harry Potter is the protagonist. He is the one with the idea of giving the troll a job. The troll is the main character as well, as the story focuses on its new life with a job. Additionally, Dumbledore might be involved. He could be either supporting Harry's decision or warning him about the potential risks of having a troll in a certain role at Hogwarts.
There could be new characters created specifically for this fanfic. For instance, some powerful advisors or generals in Naruto's 'emperor' regime. These characters could have their own motives and backstories that interact with Naruto's journey. They might be helping him build his empire or secretly plotting against him.
Since it's related to Naruto, Naruto himself is most likely a main character. He is the one becoming the eternal emperor.
Obviously, the child of the emperor would be one of the main characters. There could also be a loyal servant or bodyguard who has been with the child since birth and helps them through their trials. And perhaps an antagonist like a power - hungry noble who wants to get rid of the child to gain more power in the court.
It could be a power - hungry noble from the imperial court who sees Naruto as a threat to his own ambitions of ruling. This noble might have his own group of skilled fighters and use underhanded tactics to try and undermine Naruto's rule as emperor.