Sasuke could be one. He's highly intelligent and has his own network of contacts. He might introduce Naruto to some high - paying jobs or business opportunities. Another one is Tsunade. As the Hokage, she has access to a lot of resources and information. She could give Naruto some inside tips on how to make money, like which trade routes are the most profitable or where to find rare and valuable items.
Jiraiya might also play a role. He travels a lot and knows about different cultures and their valuable assets. He could help Naruto discover some unique items or knowledge that can be turned into wealth. Also, Shikamaru, with his brilliant mind, could come up with smart business strategies for Naruto. He could analyze the market trends in the ninja world and guide Naruto on which businesses to invest in.
Often, in these fanfictions, Naruto gets rich through his connections. He has made friends with many powerful people during his adventures. Some of these friends might offer him lucrative business deals. For instance, he could partner with a wealthy merchant from a neighboring village. Or perhaps he creates a new form of ninja training that becomes so popular that people from all over pay large sums of money to participate.
In the 'naruto becomes rich fanfiction', Naruto's wealth could allow him to have a greater influence on the political situation in the ninja world. He could use his money to support certain policies or leaders that he believes in. This might make him a target for those who oppose his views. Moreover, his rich lifestyle could make it difficult for him to relate to the common people in the village as he once did. He would have to be careful not to lose touch with his roots while enjoying his new - found wealth.
Iruka could be a surprising character to abandon Naruto in some fanfictions. Maybe he gets influenced by some outside force or a misunderstanding that makes him think Naruto is no longer the Naruto he knew. And then there are the other genin in Naruto's class. They might abandon him out of jealousy if Naruto starts showing extraordinary powers too quickly. Or they could be pressured by their families who don't want them associated with Naruto.
Obviously, Naruto will be one of the main characters. Since it's about his super luck, he's at the center of it. Sasuke might also be a main character as he often has interactions with Naruto. Their relationship could be affected by Naruto's newfound luck, whether it be through envy or cooperation. Sakura could also be a main character as she is part of Team 7 and Naruto's luck might influence the dynamics within the team.
Obviously, Naruto is a common character as it's in the title. Sasuke is also often included. He might be Naruto's rival not just in ninja skills but also in terms of popularity and wealth in the high school setting.
In 'naruto rich fanfiction', a frequent theme is the transformation of Naruto's lifestyle. With wealth, he can live in grander places and have access to luxury items. This is in contrast to his humble beginnings. Another common theme is the impact on the ninja world economy. His newfound wealth can disrupt or improve the existing economic structures. Also, the theme of self - discovery is present. Naruto has to figure out who he is now that he has money and how it fits into his identity as a ninja.
Sasuke is a likely candidate in some fanfictions. Given their complex relationship throughout the original series, it's easy to imagine a scenario where Sasuke's thirst for power or some misinformation leads him to betray Naruto. Another could be Sakura. If she becomes jealous of Naruto's growing power or if she's manipulated by outside forces, she might turn against him.
Obviously, Harry Potter himself would be the main character. His friends like Ron and Hermione would also be important as they interact with him in this new wealthy situation. Maybe some new characters could be introduced, like rich wizarding families who want to be associated with Harry or greedy businessmen in Diagon Alley who try to take advantage of his wealth.
Other pureblood characters like Draco Malfoy would surely interact with her. Given her new status, Draco might be conflicted. On one hand, she's a 'mudblood' in his old view, but now as a rich pureblood, he might have to reevaluate his attitude towards her. And there could be other pureblood families' members who would either befriend or oppose her based on their family politics.
Iruka Sensei could also be a candidate. He was one of Naruto's first supporters and has a deep connection with him. He would probably risk a lot to save Naruto.