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.
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.
Naruto himself is often involved. Since he's the main character of the original series, in fanfiction with loopholes, he might use some loophole to achieve his goal of becoming Hokage faster or getting stronger in a unique way. Sasuke could also be a main character in such fanfictions. He might find a loophole to deal with his quest for revenge or his power - seeking in a different manner.
In many Naruto scream fanfiction, Kakashi Sensei can also play an important role. He might be trying to teach Naruto how to control his scream in a more strategic way, or he could be using Naruto's scream as a signal during a mission. Also, characters like Jiraiya might be involved. Jiraiya could be training Naruto to use his scream as a form of attack or defense, as part of some new and unique jutsu.
Definitely Naruto as the victim of hypothermia. Shikamaru could also be involved. He might be the one strategizing the rescue mission, using his intelligence to figure out where Naruto could be in the cold environment. And Hinata might be there too, her concern for Naruto adding an emotional aspect to the story.
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.
Naruto himself is obviously a main character in such fanfictions. His growth in intelligence is usually the central focus. Sasuke can also be involved as Naruto's rival or ally in situations where intelligence plays a crucial role. Sakura, with her own intellectual capabilities in medical ninjutsu and general knowledge, often appears as well.