Naruto is obviously a very popular choice. His journey from a trouble - making student at the academy to a great ninja is well - known, and fanfiction can explore different aspects of his time at the academy, like his relationships with Iruka - sensei or his first attempts at learning new jutsus.
Iruka - sensei is another great character to feature. He was Naruto's first real supporter at the academy. Fanfiction can focus on his role as a teacher, his own backstory, and how he influenced the students at the academy, not just Naruto. There could be stories about his relationships with other teachers and how he tried to make the academy a better place for the students.
Naruto himself is always popular. Writers can explore different aspects of his life, like his training in more detail or his relationships with other characters in new situations.
Naruto Uzumaki himself is extremely popular. His journey from an outcast to a hero provides a rich base for fanfiction. Sasuke Uchiha is also a common choice. His brooding nature and his quest for power and revenge make for interesting storylines. Kakashi Hatake is popular too. His mysterious past and his skills as a ninja are appealing to fanfiction writers. Rock Lee is another one. His determination to succeed despite not having natural ninja talents like others is an inspiring aspect that can be explored in fanfiction.
Seth and Tory are very popular characters to feature. Their complex relationship and their roles as main characters in the original work make them interesting to write about in fanfiction. Writers can explore different scenarios for their relationship, like what if they had met under different circumstances at the academy.
Sasuke Uchiha is also a great character to feature. His complex personality and his quest for power and revenge can be explored in different ways. Maybe a fanfiction where he has to make a choice between his loyalty to the Leaf Village and his thirst for power in a new and unexpected situation.
Finn and Jake are definitely popular choices. Finn's heroism and Jake's laid - back yet powerful nature make them interesting to write about in the academy setting. They can get into all sorts of adventures together and with their friends at the academy.
Rose Hathaway is definitely a popular choice. She's strong, feisty, and has a complex personality. Her relationship with Dimitri is also a big draw for fans, so featuring her in fanfiction can create a lot of interesting storylines.
Jack Atlas is often a popular choice. His confident and somewhat arrogant personality makes for great character development in fanfiction. Writers can explore his backstory more deeply and how he interacts with the Duel Academy environment.
Naruto himself is extremely popular. He's the main character of the original series, so many fanfictions center around him. Sasuke is also a top choice. Their complex relationship gives a lot of room for fanfiction writers to explore different emotions and storylines. Sakura is often featured as well, especially in stories that focus on the trio's dynamics.
Sasuke is also a top choice. His complex personality and his own journey of redemption or further power - seeking can be explored a lot in fanfiction. He can be put in different situations in the 'naruto odyssey fanfiction' where he has to make difficult choices, which is always interesting to read about.
Kiba from Naruto can be an interesting addition to 'naruto and dxd fanfiction'. His connection with his dog and his more brash personality can add some humor and action. Akeno from DxD is also a favorite. Her seductive nature and powerful lightning - based abilities can make for some captivating storylines when combined with Naruto characters.