One possibility is that Naruto and Naruko are on a mission to save the multiverse in this fanfiction. They travel through dimensions to collect some special artifacts or powers that are scattered across different realities. Along the way, they might face challenges from the rulers of those dimensions who don't want them to take those things. This could involve epic battles and the forging of new alliances as they strive to complete their mission.
It could be some powerful dimension - hopping villains who want to use the power of different dimensions for their own evil purposes. They might see Naruto and Naruko as threats to their plans.
Perhaps Naruto travels to a dimension where everyone has a unique animal spirit companion. He has to bond with one of these spirits to gain access to certain powers. This would be a whole new experience for him as he's used to his own ninja world and its rules.
Well, one possibility is that Naruto might be really confused at first. He'd see this different version of himself as a female and might not immediately understand the situation. He could try to figure out how this time - travel happened and what it means for his world. Maybe he'd start to learn about the differences in how female Naruto is treated in this new world compared to his own experience as a male.
In this fanfiction scenario, Naruto could bring his ninja skills to the Def universe. He'd probably have to adapt to the new environment. For example, if the Def universe has different laws of physics, his usual jutsu might not work the same way. He might also learn new techniques from the Def universe and combine them with his own.
He often meets versions of himself from different dimensions. These other Narutos might have different personalities or abilities due to the differences in their respective dimensions.
One possibility is that they go on modern - style dates. Instead of going to a traditional ramen place in the Hidden Leaf Village, they might go to a trendy new café or a movie theater. Naruko could be really excited about these new experiences with Naruto.
It could be an alternate version of Voldemort from a different dimension. Maybe this Voldemort has even more powerful dark magic at his disposal.
In such a fanfiction, Naruto might try to prevent some of the tragedies that occurred in the past. For example, he could stop the Uchiha massacre. He would use his knowledge from the future to change things. Maybe he'd also be able to save some characters who died early in the original story, like Jiraiya. And he could potentially have a huge impact on the relationships between different clans, as he'd know about future conflicts.
He might accidentally change the future. For example, he could prevent important events from occurring that were crucial for the development of the present he came from. Maybe he meets his parents at a younger age and reveals too much about the future, which could cause them to make different decisions.
In this fanfiction, Aang might encounter advanced bending techniques. Since he's traveling to the future, he could see how bending has evolved over time. Maybe there are new forms of bending that combine different elements in ways he never thought possible.