The main characters are Prince Leon and Bella, of course. Prince Leon is likely to be a noble and brave character, with the responsibilities of his princely status. Bella could be a commoner or a noble as well, depending on the story. She is probably a strong - willed and kind - hearted person.
Well, Prince Leon is the prince, which means he has a certain status and expectations. He may be a bit of a rebel against some of the traditional ways of the kingdom. Bella, on the other hand, is a character full of vitality. She may be an artist or a healer in some versions of the fanfiction. Their different backgrounds and personalities are what drive the story forward as the main characters.
One possible plotline could be that Prince Leon has to go on a dangerous quest and Bella secretly follows him. Along the way, they face various challenges together and their relationship deepens.
Leon could be a wandering knight who stumbles upon the Beast's castle. He might be on a quest for something and gets involved in the story. Bella could be a village girl with a kind heart and a curious nature. She might have heard rumors about the Beast's castle and decides to explore, which is how she meets Leon and the Beast.
Typically, Naruto is a staple main character as he is the face of the Naruto series. Leon then is the new addition in this fanfiction scenario. They are often accompanied by their friends. For Naruto, that would be his comrades from the Hidden Leaf Village such as Shikamaru, who might provide strategic advice. And for Leon, if he has any allies from his own origin story, they could also be part of the story, but that depends on how the author of the fanfiction writes it.
The main character is always Bella in this type of fanfiction. However, new characters could be introduced as well. For instance, a blind mentor who has learned to live fully with blindness could be added. This character could guide Bella and help her accept her condition. Or there could be a villain who tries to take advantage of Bella's blindness, which would then lead to a conflict where Bella has to use her wits and other strengths to overcome the villain.
There could be Edward. Even if Bella is now immortal, Edward might still play a significant role. He could be either her eternal love or her adversary depending on how the fanfiction is written. Another character could be Alice. Since Alice has her own special abilities, she might be there to help Bella navigate the new world of immortality. For example, she could foresee some of the challenges that Bella will face. Also, Jacob might be a main character. His relationship with Bella, whether it's a friendship or something more complicated, could be further explored in the context of Bella's immortality.
There could be Edward. Maybe he is involved in Bella's life with her psychic powers. He might be curious about her abilities or even try to protect her from the consequences of using those powers.
There could be a female character, Sofia, who is another member of the mafia. She sees Bella as a threat at first, thinking she'll steal her position or the attention of the men in the mafia. But as time goes on, they might form an unlikely alliance. There may also be a young and ambitious mafia underling named Antonio, who is always looking for ways to climb the ranks and his actions often impact Bella's situation in the story.
Another plotline could be that Bella is not the typical damsel in distress. She has some special power, like being able to communicate with the enchanted objects in the castle. Leon, on the other hand, is a rival for the Beast's affection towards Bella. This creates a love triangle situation that adds drama to the fanfiction.
Edward is often paired with Bella in such fanfiction. Since he is a vampire in the original story, the dynamic between a dhampir Bella and vampire Edward can be very interesting. There could be a lot of tension and new plotlines. Another character could be Jacob. His werewolf nature could add another layer of complexity to the relationship when Bella is a dhampir.
Well, it could be the people she targets. They would be important as they drive the action when Bella is on her 'killer missions'.