The older brother in the fanfiction might be a character with a tragic past. For example, he could have been experimented on by Orochimaru and gained some strange powers as a result. And he returns to the village later to protect Naruto from the threats that are coming towards him.
Maybe Naruto discovers a conspiracy within Konoha while he's in the ANBU. It could involve some of the higher - ups trying to gain more power at the expense of the village's well - being. Naruto then has to decide whether to expose it and risk his position or try to solve it quietly.
One great 'older Naruto Anbu' fanfiction is 'The Anbu's Redemption'. It focuses on Naruto's experiences as an Anbu member later in life and how he overcomes various challenges. Another is 'Naruto: Anbu Ascendant' which delves into his growth within the Anbu ranks and his relationships with other Anbu members.
Well, in this fanfiction idea, Naruto being Sona's older brother could bring a whole new dynamic. Maybe Naruto's protective nature would extend to Sona. He could teach her some of his ninja skills and values like never giving up. It could also create interesting interactions with the other characters in their respective universes. For example, how would the devils in Sona's world react to Naruto's presence? And how would Naruto handle the political aspects of Sona's world which are quite different from his own ninja village politics.
There could be. Fanfiction writers like to explore different 'what - if' scenarios. Since Naruto and Kushina have a strong connection in the original series, some writers might be intrigued by the idea of reversing their relationship in a fictional context. But it goes against the established lore of the main Naruto storyline.
In some fanfictions, it's possible for Naruto to be depicted as Anko's older brother. Fanfiction often takes creative liberties with established characters and their relationships.
If Naruto was the older brother of Kushina, it would rewrite a lot of the backstory. For one, Naruto might be the one to introduce Kushina to Minato. He could see Minato's potential and think he would be a good match for his sister. Also, Naruto's skills and abilities could have a different origin. Maybe he learned some things from Kushina or their family that were unique. This would change his fight scenes and how he approaches challenges in the fanfiction. He might also have a different relationship with the Uzumaki clan as a whole, having more of a family - based influence within it.
One idea could be that Naruto, with his strong sense of justice and loyalty, helps Rias in the supernatural politics of her world. He might use his ninja skills to protect her and her peerage from other devils or threats. For example, when facing a powerful rival devil clan, Naruto's shadow clone jutsu could create a diversion while Rias plans a strategic attack.
In a fanfiction where Naruto is Madara's older brother, it could completely change the Naruto universe's dynamics. For example, Naruto's ideals of peace and friendship might have influenced Madara at a young age, preventing him from going down the dark path he did in the original story. Naruto could have taught Madara about the power of bonds, which was something Madara seemed to have lost sight of later in his life. This would lead to a different series of events, perhaps even averting the many wars that took place in the Naruto world.
Yes, there are likely some fanfictions with this concept. Fanfiction writers often explore unique relationships and alternate storylines. They might create a scenario where Naruto is Sasuke's older brother to develop different character dynamics, explore new plotlines, and add their own creative twists to the Naruto universe.