Sometimes, it's an existing Naruto character who is given the Light Release bloodline in an alternate universe story. For example, Naruto himself could be given this bloodline, which would change his fighting style completely. He could use his natural exuberance and combine it with the light powers to create some really unique and powerful jutsu.
Another possibility is that a member of a minor clan in the Naruto world is the main character. They might have been overshadowed by more well - known clans, but with the discovery of their Light Release bloodline, they rise to prominence and play a crucial role in the story, whether it's in battles against the Akatsuki or in protecting their village.
Naruto himself is often a central character. Since he has his own unique chakra nature and potential, fanfictions might explore how his own abilities interact with different bloodlines. Sasuke is also common, given his Sharingan bloodline. Hinata could be involved as her Byakugan bloodline is quite interesting. And sometimes, new or original characters created specifically for the fanfiction might also be main characters, especially if they possess some sort of rare or infamous bloodline.
Naruto himself is obviously a main character in most of these fanfictions. Since it's about the Namikaze bloodline and he's the son of Minato Namikaze.
Often, Naruto himself might be involved as he is the main character of the original series. He could be the one to discover or master a new particle release. Sasuke could also be a main character in such fanfiction, perhaps using his Sharingan in combination with particle release in unique ways.
There might be a mentor figure, an older ninja who has some knowledge about the crystal release bloodline, even if they don't possess it themselves. They guide the young character in understanding and using their powers. For example, they might teach the protagonist how to shape the crystals into different forms like weapons or shields. Another common character could be an antagonist who covets the power of the crystal release bloodline and tries to either steal it from the protagonist or prevent them from fully realizing its potential.
Sasuke is often involved. Given his natural inclination towards power and his Sharingan, it's easy to imagine him exploring the Meiton Release. His quest for power could lead him to discover and master this dark release. Another one is Naruto himself. Fans might write about Naruto learning Meiton Release to add a new dimension to his already vast arsenal of jutsu, perhaps as a way to face an even stronger enemy.
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.