Well, aside from Naruto, Rock Lee can be quite popular in Blood Prison fanfiction. His determination and unique fighting abilities can add an interesting dynamic to the prison environment. Also, Orochimaru might be a character that shows up a lot. His thirst for knowledge and dark experiments could be linked to the secrets that the Blood Prison might hold, making him a character full of potential in these fan - made stories.
Naruto is a given as the main character, but Sasuke can also be a popular choice in Naruto Blood Prison fanfiction. Writers might explore the idea of Sasuke ending up in the Blood Prison and how he would interact with Naruto there. Then there's Killer Bee, who could bring his unique fighting style and personality to the prison setting, making him an interesting addition to fan - created stories.
Obviously, Haren is one of the main characters. There might also be the prison guards who play significant roles in creating conflict or helping Haren. Another could be a mysterious inmate who has some knowledge about Haren's past or the secrets of the Blood Prison.
The main character is Naruto, as it's a Naruto - centered fanfiction. But in the Blood Prison setting, there could be other key characters. For example, the warden of the prison who might be a cruel or mysterious figure. Also, there could be a fellow inmate who has a special connection with Naruto, either as a friend or a rival. These characters play important roles in driving the story forward in the context of the dark and dangerous Blood Prison.
In this fanfiction, Naruto will surely interact with his friends who might be trying to break him out or at least communicate with him from the outside. Inside the prison, he'll encounter inmates with diverse personalities. There could be a wise old prisoner who imparts some valuable wisdom to Naruto. Also, there may be a group of inmates who form a sort of gang within the prison, and Naruto has to either fight them or make peace with them depending on the situation. And of course, there could be a mysterious figure who seems to know more about Naruto's presence in the prison than he himself does, and Naruto will have to figure out this person's motives and identity.
Some fanfictions might also feature the prison guards as main characters. They could be complex characters with their own motives and backstories, and their interactions with Naruto could drive the plot forward. For example, a guard who initially sees Naruto as just another prisoner but then comes to respect him.
Naruto is a very likely character. Given his rebellious nature and his history of being an outcast in some ways, it's easy to imagine a scenario where he gets caught up in something that lands him in prison. His determination to break free and his loyalty to his friends would make for an interesting story.
Naruto himself is often a popular character in these fanfictions. Writers like to explore how his existing powers could interact with blood mage abilities. Sasuke is also a common choice. His Sharingan and his quest for power could be combined with blood magic in interesting ways.
Kakashi is another character that could be popular in 'naruto blood manipulation fanfiction'. His Sharingan and his intelligence could be combined with blood manipulation. For example, he could use his knowledge of the Sharingan to better understand the flow of blood in the body and develop new jutsus. Sakura, with her medical ninjutsu knowledge, could also be a major character. She might start exploring blood manipulation to enhance her healing abilities, perhaps finding a way to use it to revive the critically injured. And there's always the possibility of new original characters being created specifically for these fanfictions, with their own unique blood manipulation abilities.
Perhaps there is a powerful and mysterious figure lurking in the shadows of the Blood Prison. This character has a vendetta against Naruto and uses the prison's environment and its inmates to try and bring Naruto down.
Naruto himself could be a likely main character. Given his determination and his ability to make friends, it would be interesting to see him in a harem situation within the Blood Prison. He could use his ninja skills to protect the harem members and try to break free from the prison's mysteries.
Eve is a very popular character. His mysterious allure and powerful musical skills make him an interesting subject. Writers can explore his past and how he became such a dominant figure in the Visual Prison.