Naruto Uzumaki could also be popular. Although he doesn't have the Rinnegan in the original story, in fanfiction, the idea of Naruto somehow obtaining or being affected by the Eternal Rinnegan can create some really exciting storylines. His never - give - up attitude and his role as the hero of the village would bring a new dimension to the story with this new power.
Sasuke Uchiha is often a popular choice. Given his natural Uchiha abilities and his connection to the Rinnegan in the original Naruto story, he's a likely candidate in fanfiction. His brooding nature and quest for power make him a great character to explore further with the added power of the Eternal Rinnegan.
Kakashi can be quite popular too. His wisdom and experience could play a role in guiding Naruto as he deals with the power of the Rinnegan. Also, fans might be interested in seeing how Kakashi reacts to Naruto's new - found power and how it might affect their bond.
Pain is often a very popular character in Rinnegan fanfiction. His original use of the Rinnegan in the series made him quite an interesting character, and in fanfiction, people like to explore his backstory further or give him new powers. Nagato, who was the original owner of Pain's body, is also popular. He has a complex history and his connection to the Rinnegan can be explored in many ways.
There could be an original character created specifically for this fanfic. This character might be the one who actually has the eternal rinnegan and is central to the story. Their backstory, motives, and relationships with other Naruto characters would drive the plot forward.
Madara Uchiha is another character who could be a main focus. Given his connection to the Uchiha clan and his own powerful Sharingan - related abilities, fanfiction could expand on his story by giving him the eternal mangekyou rinnegan and exploring what he would do with this even greater power.
Well, Obito Uchiha can also be considered an iconic character in Rinnegan - related fanfictions. His connection to the Sharingan and his later acquisition of the Rinnegan through various means is a rich area for exploration. And, there could be an ancient ancestor of the Rinnegan Clan, a character only mentioned in the fanfiction, but whose legend looms large over the clan and its members.
In Rinnegan Naruto Clan Wars fanfiction, a character like Nagato could be really interesting. He already had the Rinnegan and his story could be further explored in the clan wars setting. Maybe he could be a key figure in a new clan or an outcast trying to regain his power. Another interesting character could be a new OC (Original Character) created specifically for this fanfiction. This OC could be a young ninja who discovers they have the Rinnegan and has to navigate the dangerous world of clan wars. And Kakashi could also be an interesting character. His Sharingan experience might give him some unique insights when dealing with the Rinnegan - wielding opponents in the clan wars.
There could be an original character created in the fanfiction who has a unique form of the Rinnegan. Maybe they have combined it with another kekkei genkai, making them a powerful force. Such a character could have abilities that are unheard of and thus be one of the most powerful.
In Percy Jackson eternal fanfiction, Percy is no doubt one of the most popular characters. Fans love to write about his new quests and how he overcomes challenges. But also, Grover Underwood has his fans. His loyalty and his unique role as a satyr are often highlighted in fan - created stories. Additionally, Clarisse La Rue is quite popular in some fanfictions. Her tough - girl attitude and her growth as a character are explored in different and interesting ways.
Sasuke is often a common character. Given his connection to the Uchiha clan and his own powerful ocular abilities, it's easy to imagine him being involved in a story about sharing the Rinnegan. He could be a key figure in either using the shared Rinnegan for good or being tempted by its power.
Naruto himself is often included as he has a central role in the Naruto universe. Also, characters like Hinata, Sakura might be part of the harem. And Sasuke could also be involved in some way, either as a rival or an ally to the main character with the Godlike Rinnegan.