One possibility is that they are in a mentor - mentee relationship. Gaara, with his experience and power, could be teaching Matsuri new techniques and ways to protect the village. Matsuri, being eager to learn, would be a great student for him. And this relationship could also evolve into a deeper friendship over time as they face challenges together in the fanfiction world.
Matsuri's character could be developed as someone who is inspired by Gaara. She may strive to be like him in terms of strength and leadership. In fanfiction, she could be shown following Gaara's example in handling difficult situations. At the same time, her presence can also bring out a softer side of Gaara, as he might be more protective of her. Their relationship can be a tool to explore different aspects of both of their personalities.
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.
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.
They're similar in their tenacity. Naruto never gives up, no matter how tough the situation is. He keeps fighting against powerful enemies like Pain or Sasuke. Gaara is the same. He has faced numerous challenges, especially when dealing with the internal and external threats to his village. Despite his past traumas, he stands firm. Also, they both understand the pain of being an outcast, which makes them empathetic towards others who are suffering.