The Hokage at that time, whether it's Tsunade or someone else, would surely be part of the story. They would need to assess Naruto's situation and how his return could impact the village. Hinata is also a very likely character. Her feelings for Naruto are well - known, and his return would be a big moment for her. Then there are Naruto's other comrades from Team 7, like Sasuke. Even if Sasuke has his own journey, his relationship with Naruto makes his appearance in a Naruto - going - home fanfiction quite possible.
Definitely Gaara. He and Naruto have a special bond, and Gaara might come to Konoha to welcome Naruto back or be involved in some way related to Naruto's journey home. The other Kage from different villages might also be mentioned or even make an appearance if there are diplomatic or political implications of Naruto's return. And the old - timers in Konoha like the Third Hokage's spirit (if it can be manifested in some way) could also play a role as Naruto returns to the place that the Third Hokage once watched over.
Sakura would be very likely to appear. She's Naruto's friend and has always been an important part of his life in Konoha. Kakashi too, as Naruto's former sensei. He would be interested in Naruto's growth and return. His friends like Shikamaru, who is smart and has always been there for Naruto in different situations. And of course, Iruka - sensei, who was like a father figure to Naruto in the beginning. He would be overjoyed to see Naruto come back home.
Obviously Naruto himself is very likely to appear. He is the main character after all. Sasuke would also be a common character as his relationship with Naruto is so central to the story. Then there are the important figures like the Hokages, especially the ones like Minato and Hashirama who had a big impact on Naruto's life. And of course, characters like Kakashi who played a major role in Naruto's growth.
Obviously, the 5th Hokage herself. Then there would probably be Naruto, as he is a central character in the Naruto universe. Sakura might also be there, as she is one of Naruto's closest friends. And Kakashi could make an appearance, given his importance in the story. Shikamaru, with his intelligence, could also be involved, perhaps as an advisor to the 5th Hokage.
Sasuke would be a likely character to appear. Since he and Naruto have a deep connection, Sasuke might cross paths with Naruto during his wanderings, either as an ally or an antagonist depending on the plot.
Iruka would be a likely candidate. He was Naruto's first teacher and has always cared about him. He would probably notice the signs early on and try his best to bring Naruto back from the brink of insanity. He might use his kind words and the bond they share to reach Naruto.
Iruka sensei is almost certain to be in it. He has always been important in Naruto's life. Also, Sakura might be there. She could be one of the first to welcome Naruto or perhaps she might initially be a bit cold because of her past feelings for Sasuke. Other characters like Kakashi sensei could also make an appearance, guiding Naruto in his new life in Konoha.
Obviously Naruto himself. And from the 'Death' side, the Shinigami is very likely to show up. It's the most iconic death - related character in that universe.
The central character would be the Avenger of Shinjuku. But also, there could be characters who are the Avenger's former allies or enemies from their past. In Shinjuku, we might see some ordinary citizens who get caught up in the chaos caused by the Avenger. There could also be other Servants who are in Shinjuku for their own reasons, such as seeking power or fulfilling a personal quest, and end up interacting with the Avenger.
Naruto, Sasuke, and Sakura are the most obvious choices. They are the main characters and their interactions are always interesting. Naruto would bring his energetic and fun - loving nature, Sasuke his brooding intensity, and Sakura her intelligence and strong - willed personality.
Naruto himself could be in jail fanfiction. Maybe he was framed for a crime he didn't commit and has to prove his innocence from within the prison. Sasuke is also a likely candidate. His brooding and sometimes anti - social nature could lead to him getting into trouble with the law in a fanfiction setting. Another one could be Orochimaru. Given his history of unethical experiments, it's not hard to imagine him ending up in jail in a fan - created scenario.
Sasuke is very likely to appear. Since he and Naruto have a deep bond, he would surely come to Naruto's aid when it comes to saving his family. Also, Sakura, as Naruto's teammate and a powerful ninja in her own right, would be there. Kakashi could also make an appearance, providing guidance and wisdom to Naruto, just like he did when Naruto was younger.