Sure. The characters are a huge part of Naruto Shippuden fanfiction. Fanfic writers use the characters to attract readers who are fans of those characters. They might focus on a character's backstory that wasn't fully explored in the anime and expand on it. Also, the interactions between characters in the original show give fanfic writers ideas for different scenarios in their stories.
By their unique abilities. Naruto's Rasengan, Sasuke's Sharingan, these abilities can be the starting point for many fanfiction ideas. Writers can think about how these abilities could be used in different battles or situations not shown in the original.
One of the most popular is 'Naruto Shippuden: Sakura Hiden - Thoughts of Love, Riding Upon a Spring Breeze'. It's popular because it shows Sakura in a new light, with her own adventures and growth.
In the Naruto saves Karin fanfic, the act of saving Karin by Naruto can have a profound impact on their relationship. Karin has always been on the periphery of Naruto's world, but this event would bring her closer. She may start to believe in Naruto's ideology more strongly. Naruto would also develop a more protective stance towards Karin. This new dynamic could lead to more interactions between them in the future, both in battle and in more personal, emotional situations.
Naruto, having been banished, may initially lose his sense of purpose. However, with Karin by his side, he could find a new reason to strive. He might develop a more nuanced view of the ninja world and its politics. Karin, on the other hand, could develop a softer side. She has always been in a tough situation, but Naruto's kindness could make her more empathetic. She may also start to trust others more, especially Naruto, which is a big step for her character.
I don't think it's strange at all. Naruto is a very curious person. Fanfiction can offer new perspectives on his own life and the lives of his friends. He might learn something new about himself or get inspired by the creative ideas in the fanfiction. It could also be a form of entertainment for him during his downtime.
A Naruto x Hinata fanfiction could focus on a mission they go on together during Naruto Shippuden. They are forced to rely on each other in a dangerous situation. Hinata gets injured protecting Naruto, and Naruto is filled with a new - found determination to protect her. This experience deepens their bond, and Naruto starts to see Hinata in a whole new light, leading to the start of their romantic relationship.
Well, normal Naruto Shippuden fanfics are likely to be centered around the adventures, growth, and battles of the characters. They might explore different what - if scenarios within the framework of the Naruto universe. But 'naruto shippuden diaper fanfic' is likely to be more of a novelty or a very specific and strange take on the characters. It might not have the same depth or connection to the original story as normal fanfics do. For example, normal fanfics could focus on how a character overcomes a difficult battle, while a 'diaper fanfic' would be more about a really odd situation involving diapers which has little to do with the main Naruto themes.
Another interesting novel is 'Naruto Shippuden: Kakashi Hiden - Lightning in the Icy Sky'. It focuses on Kakashi's story and his past, which is really fascinating. There are a lot of details about his relationships and his growth as a ninja.
In this fanfiction scenario, their relationship would be deep - rooted in family love. Naruto would look up to Karin as an older sister, or if Karin was younger, he would be very protective. They would likely have a bond that goes beyond the typical shinobi comradeship. Karin could be the one to understand Naruto's loneliness as a child, and Naruto could be the one to bring out Karin's softer side. They might even develop a unique form of teamwork, combining Naruto's powerful jutsu with Karin's healing and sensing abilities for their adventures.