Another character that could be involved is Kakashi. He is a very experienced ninja with a lot of knowledge. In fanfiction, he might be the one who guides the younger ninjas in understanding and using a legendary summoning contract. Or, he could have his own history with such a contract that is revealed as the story progresses, adding depth to his character within the fan - made narrative.
Naruto himself is often a main character. Given his adventurous nature and his own experiences with summoning, it's easy to imagine him getting involved with a legendary summoning contract in fanfiction. He might discover it during one of his quests or it could be passed down to him in a mysterious way.
Often, Naruto himself can be one of the main characters. Since he's always looking for new ways to get stronger, the raven summoning contract could be something he discovers and tries to master. Another could be Sasuke. Given his connection to the Uchiha clan and their association with birds in a way, it would make sense for him to be involved in stories related to raven summoning.
It could be a side character from the original Naruto series who wasn't given much spotlight before. They find the hellhound summoning contract and it changes their role in the story completely. For example, a previously weak or overlooked ninja suddenly becomes a force to be reckoned with thanks to the hellhounds.
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.
Sasuke is also commonly involved. His own journey of self - discovery and redemption is a rich area for fanfiction writers. His complex past and his actions that have caused harm in the Naruto world make his redemption arc an interesting topic to explore, especially in relation to how he reconciles with Naruto and the rest of the village.
Sakura could also be a main character in such fanfiction. Given her intelligence and medical skills, she might be working in the lab, conducting research on new ways to heal ninja injuries or even enhance their physical abilities through some sort of medical - ninja technology combination.