I think Shanks would have an interesting reaction. He has known Luffy since he was a kid. Seeing Luffy reach Gear 5, he would probably be proud but also a bit cautious. He might think about how far Luffy has come and also wonder what challenges this new power will bring for Luffy and the world at large.
Luffy would probably be super excited. He's always been on this big adventure, and meeting his dad would be like a new milestone. He might jump up and down and start asking a million questions right away, like what his dad has been doing all this time and if he has any cool stories from his own adventures.
He might be either very amused or highly offended. If he had a sense of humor, he could find the creative and often out - of - the - box ideas in fanfiction quite entertaining. However, if he was a traditionalist, he might be offended by the liberties taken with his image or the storylines that might not align with the official version of things.
There is also a 'luffy emperor fanfiction' where Luffy has to deal with new political challenges in the pirate world as an 'emperor'. In this fic, his relationships with other pirate crews are explored in a whole new light, and his leadership is tested in various diplomatic situations.
One potential new ally could be a powerful pirate from the past. For instance, a pirate who was known for his great navigation skills. Luffy could use his help to explore uncharted seas more easily.
There could be some of Dragon's comrades in the revolutionary army who become important figures in Luffy's upbringing. For example, a veteran revolutionary who teaches Luffy about the history of the world and the wrongdoings of the World Government.
One potential new member could be a skilled archer from a forest - dwelling tribe. They have amazing accuracy and can use special arrows made from rare materials found only in their forest. Another could be a mermaid or merman with the ability to control water in unique ways, not just for combat but also for things like navigation and finding hidden treasures.
They might be quite amused. Bella could find it interesting to see different takes on her relationship with Edward during that difficult time in New Moon. The Cullens, especially the more light - hearted ones like Emmett, might get a good laugh out of some of the wilder interpretations in the fanfiction.
The gods could have a range of reactions. Some might be dismissive if the fanfiction doesn't align with their view of the Naruto world. Others could be highly entertained and might even start to daydream about the scenarios presented in the fanfiction. There's also a chance that they would feel a sense of admiration for the creativity of the fanfiction author in coming up with the 'emperor Naruto' concept.