Another option could be Mangetsu Hozuki. Even though he's not as prominent as Suigetsu, his reputation as a powerful Hozuki ninja could be explored. A fanfic could be about his unfulfilled dreams and how he might have influenced the Hozuki clan if he had lived longer.
Suigetsu Hozuki is a well - known character. He has a laid - back yet determined personality. A fanfic could focus on his past before joining Sasuke's team, perhaps his training and how he came to master his water - based abilities.
Shikadai is quite popular. His laid - back yet intelligent nature makes for an interesting character to write about. Inojin and Cho - Cho are also good choices. You can focus on their growth as ninja, their relationships with their parents' generation, and how they contribute to the new ninja world in the 'naruto gaiden fanfic'.
Sasuke is always a popular choice. His complex backstory and his journey of redemption can be explored further in fanfics. Writers can delve into his internal struggles, like his feelings towards his clan and his relationship with Naruto in more depth.
Sasuke is a very popular choice. His complex backstory and brooding personality offer a lot of room for exploration. Fanfictions can delve deeper into his time with Orochimaru, his family's past, and his relationship with Naruto from a different perspective.
Yuki is a very popular character to focus on. She has a complex backstory, being raised among vampires and having a special connection to both the vampire and human worlds. Her relationship with Zero and Kaname also offers a lot of material for fanfic writers to explore, such as her inner conflict between her love for both of them and her duty to maintain the peace at Cross Academy.
Nagisa Shiota is also very popular. Fanfics could focus on his growth as an assassin and how his initially meek personality evolves over time. His unique skills and his friendship with other classmates can be great elements to build a story around.
Louise is a very popular character to focus on. She has a complex personality, being proud yet often insecure. Her growth as a mage throughout the series can be further explored in a fanfic, especially her relationship with her magic and how it evolves.
The Mad Hatter is also popular. You could write about his tea parties in more detail, or create a story where he loses his 'madness' and has to find it again. Maybe Alice has to help him in this journey of self - discovery.
Rick Grimes is always a popular choice. His leadership skills and the moral dilemmas he faces can be explored further in fanfic. Daryl Dixon is another fan - favorite. You can write about his backstory, his survival skills, and his relationships within the group. Michonne is also great to focus on, with her katana - wielding badassery and her complex personality.
In a Crystal Story 2 fanfic, the merchant character can be really interesting to focus on. You could write about how they acquired all their wares, their relationships with suppliers in different parts of the game world, and any secrets they might be hiding. The mysterious hooded figure that appears briefly in the game can also be a great character to write about. You can create their backstory, their goals, and their connection to the main plot of the game. And don't forget about the pet - like creatures in the game. You can write a fanfic from their perspective, showing their loyalty to their owners and their own little adventures within the game world.
The protagonist is always a popular choice. You can develop their character further, explore their unspoken thoughts and feelings, and put them in new situations. For instance, in a 'breach of fate' fanfic, the main character might face a moral dilemma that wasn't in the original story.