Obviously, the Indra transmigrant is a main character. Naruto himself might also be involved as he has a connection to the whole Indra - Asura cycle. Sasuke could be another key character as he is also related to this cycle in the Naruto lore.
In this type of fanfiction, the Indra transmigrant is central. But often, characters like Kakashi could be involved too. Since he is a mentor figure, he might play a role in guiding the Indra transmigrant. Also, the Akatsuki members could be part of the story. They might be interested in the power of the Indra transmigrant and try to either recruit or eliminate them.
Often, Naruto himself is a main character in such fanfiction. Since he is the protagonist of the original series and the story might explore how Indra's legacy affects him. Sasuke is also likely to be involved as he has a connection to the Uchiha clan which has ties to Indra. Madara Uchiha could also be a prominent character as he was deeply influenced by the legacy of Indra.
Well, Naruto and Sasuke are the central ones for sure. But other characters like Jiraiya might also be important. Jiraiya could have known something about Naruto's true nature as the reincarnation of Indra all along and his teachings could be seen in a new light. Additionally, the Kage of the different villages might also be main characters as they deal with the implications of Naruto's new status.
One interesting idea could be exploring how the Indra transmigrant copes with the memories and powers. For example, they might struggle to control the immense power which could lead to some internal conflicts.
Naruto and Sasuke are often the main characters focused on since Naruto is the reincarnation of Ashura and Sasuke is the reincarnation of Indra in the Naruto series.
Obviously Naruto himself is a main character. He is the one with the pacemaker so he is central to the story. Sasuke might also be involved. He could be initially skeptical of Naruto's new situation with the pacemaker but then come around to help. Sakura too, as a medical ninja, she could play a crucial role in understanding and perhaps even trying to modify the pacemaker.
Naruto is almost always a main character in 'naruto dice fanfiction' as the story is based on the Naruto universe. His friends like Sasuke and Sakura also often appear. Sasuke's cool and brooding nature can add an interesting dynamic when combined with Naruto's more upbeat and impulsive personality in stories related to the dice.
Kakashi could be a central figure in such fanfiction. His Sharingan and combat expertise would make him an interesting character to be associated with a special knife. He could use his knowledge to teach others about the knife's proper use. Another character could be Sakura. If she gets hold of a knife with unique healing properties, she could use it to both heal and fight, adding a new dimension to her character in the fanfiction.
Obviously Naruto himself is the central character. Sakura might also be involved as she could be one of the few in the village who believes in Naruto's innocence and tries to help him from afar.
Well, Naruto himself is obviously a main character as it's about his regeneration. Sasuke might also be involved as his rival and friend. Their relationship could be explored in new ways with Naruto's regeneration, like Sasuke being jealous or worried about Naruto's new power.
Obviously Naruto himself is often a main character. His adventurous spirit and determination make him a natural fit for stories involving Gelel. Another common character is Sasuke. His power - hungry nature could be interested in Gelel's power, leading to some interesting plot twists.