Well, Naruto is obviously one of the main characters as it's about him being the heir of darkness. Sasuke could also be a major character as his relationship with Naruto is always a central aspect in Naruto - related stories. Sakura might also play an important role, perhaps being one of the first to notice the changes in Naruto due to his new status.
The main character is the 'Heir of Darkness', who has a complex personality and backstory. Harry Potter would be a main character as he is often at the center of any major events in the Harry Potter universe. Additionally, there could be antagonists in the fanfiction related to the dark side that the heir might be associated with. For example, a group of dark wizards who want to use the heir for their own evil purposes. And the fanfiction might also introduce some minor characters from the original series in new roles, like Luna Lovegood providing some unique insights about the heir's situation.
There could also be some well - known Naruto characters who play important roles in the story. For instance, Naruto or Sasuke could be involved, either as mentors or as characters who are somehow related to the events involving the heir. Maybe Naruto helps the heir come to terms with the deaths they are associated with, or Sasuke has some knowledge about the secrets behind the deaths that the heir needs to know.
Obviously, the heir of Madara would be a main character. There might also be other characters from the original Naruto series, like Naruto himself. Naruto could be in opposition to the heir, seeing them as a threat to the peace he has worked so hard to achieve.
Obviously Naruto would be one of the main characters. There might also be his usual friends like Sasuke and Sakura. But since it's a fanfiction about him being the heir of chaos, there could be new characters introduced who are related to this chaos aspect, like some ancient beings or a secret clan.
Obviously Naruto would be one of the main characters since it's about him being the heir of Kaguya. Sasuke could also be a main character as Naruto's rival and friend. Sakura might be involved too, as she is part of Naruto's team. And there could be other characters like Kakashi, who would play a role in guiding Naruto as he discovers his new identity. There might also be some new characters introduced that are related to Kaguya's past, who either help or hinder Naruto on his journey.
Obviously Naruto would be one of the main characters since it's about him being the heir to the Uzumaki. Sakura and Sasuke might also be important characters as they are Naruto's friends and comrades. There could also be some original characters created specifically for the fanfiction, like an old Uzumaki sage who guides Naruto on his journey as the heir.
Since I don't know the specific 'naruto kami heir fanfiction', it's hard to say for sure. But it could be a new character who is the heir, maybe a descendent of an important figure in Naruto lore. It might also include well - known Naruto characters like Naruto himself, Sasuke, or Sakura who interact with this heir character.
Well, Naruto is surely a main character. And depending on the plot, characters like Kakashi could be important. He's Naruto's teacher and might try to guide Naruto away from the allure of darkness. Also, Orochimaru could be a key figure. He's always been associated with dark arts in the Naruto series, and in this fanfiction, he might play a role in Naruto's exploration of the darkness, either as an ally or an enemy.
The main characters would surely include Naruto. Then, depending on the direction of the fanfiction, characters like Jiraiya could be important as he might be the one to help Naruto understand and control his dark side. There could also be some dark - themed characters that are part of Naruto's heritage or the source of his 'son of darkness' status. And of course, his friends, even if they are initially wary of him, would still be key characters as they react to Naruto's transformation or discovery of his new identity.
Most likely Naruto would be one of the main characters. Depending on the crossover, it could also include characters from the other franchise involved in the crossover.