Sasuke would also be a key character. His past actions during the war need to be reconciled, and he could play a role in training the next generation of ninjas, passing on his unique skills.
Obviously, Naruto would be a main character. His determination and powerful jutsu would be crucial in the rescue mission. Gaara, the Kazekage himself, would also be a central figure even though he is the one being rescued as his past and his role in the shinobi world are important aspects.
One of the most memorable arcs is the Pain's Assault arc. In this arc, Pain attacks Konoha, and Naruto returns to face him. It shows Naruto's growth as he not only battles Pain but also tries to understand his motives. Another great arc is the Itachi Pursuit Mission arc, which reveals a lot about Itachi's true nature and his sacrifices for Sasuke.
Sasuke could also be a main character. His power and his complex relationship with Naruto would play a role. He might have his own reasons for wanting to either defeat or control the Beast of War, perhaps related to his quest for power or revenge. And Sakura, with her medical ninjutsu skills and her growth as a fighter, could be crucial in treating the wounded during the battles against the beast. She might also have some unique insights into the nature of the beast based on her studies.
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.
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.
Naruto and Sasuke would be very likely to interact. If Naruto has God of War powers, Sasuke might be curious or even envious. They could have a fight or a conversation about these new powers. Another pair could be Naruto and Kakashi. Kakashi would surely be interested in Naruto's new abilities and how they could be used for the village.
Naruto himself is very likely to have a significant role. He is the main character of the original series, and his strong will and unique abilities would be crucial in any time - traveling adventure. His determination to protect his friends and the ninja world would drive the plot.
Obviously Naruto would be the main character since it's about him time - traveling. Sasuke would also likely play an important role. Maybe he's skeptical of Naruto's time - traveling claims at first but then comes to believe him and helps him change things. Kakashi could also be a major character, providing guidance to Naruto based on his own experiences.
Hinata is a very likely character. She already has a deep connection with Naruto in the original series, so in a harem fanfiction, she could be part of it. Sakura might also be included. Despite her initial feelings for Sasuke, in this type of fanfiction, her relationship with Naruto could change. And then there's Ino. She's a strong - willed character who could be attracted to Naruto's new God of War - like qualities.
Sasuke would likely be more critical. He'd scoff at some of the fanfiction that portrays him inaccurately. But he might also secretly enjoy the ones that show his growth and development in a new light. He'd be all like 'This one has some truth to it, but this other one is just nonsense'.