It could be Jiraiya. He has a really strong bond with Naruto already. He's taught Naruto a lot in the original story too. So in the fanfic, his training could be the most in - depth, covering things like advanced rasengan variations and how to fight against really powerful enemies. His influence on Naruto's character development would also be significant.
The 'naruto legendary sannin fanfic' can be a great way to experience the Naruto world from a different perspective. It may introduce new characters that interact with the Sannin, which could add more layers to the story. The fanfic might also explore the emotional aspects of the Sannin, like Tsunade's struggle with her past losses, Orochimaru's quest for power and immortality from a more psychological angle, and Jiraiya's hope for a better future for the ninja world through his relationship with Naruto.
Jiraiya would be the most interesting. He has a wild and carefree personality which could be a great contrast to Naruto's initially lonely and neglected state. Jiraiya is also very knowledgeable about the outside world and has many powerful jutsus, especially those related to the toads. He could take Naruto on adventures, teaching him not just about being a ninja but also about life in general. His connection to the prophecy about the 'Child of Prophecy' could also add an interesting layer to the story, as Naruto might be groomed in a different way to fulfill that prophecy under Jiraiya's guidance.
It's hard to say for sure without reading it, but likely there will be three main characters who are the new sannin. They could be students of the original sannin or completely new characters with no direct connection but similar in their skills and importance.
The unique personalities of the Sannin make the 'naruto legendary sannin fanfic' interesting. Jiraiya is the carefree yet wise teacher, Orochimaru is the power - hungry and mysterious villain - like figure, and Tsunade is the strong - willed and sometimes stubborn medic - ninja. Their interactions are always full of drama and tension.
Well, it could be that Naruto gets super powerful training from each of the Sannin. Jiraiya might teach him more advanced toad jutsus and how to better control his chakra. Tsunade could train him in medical ninjutsu and physical combat skills. Orochimaru, even though he's a bit of a dark character, could show Naruto some really unique and forbidden jutsus that Naruto has to learn to resist the dark side of. And all this special training could make Naruto a much more formidable shinobi in the fanfic.
Perhaps they are three young wizards from a far - off land. They could be from a place where magic is practiced differently, like a tribe deep in the Amazon where they use magic to communicate with animals. So when they come to Hogwarts, they have a lot to learn and also a lot to teach. They might have unique magical abilities that are rare in the Hogwarts world, such as the ability to control the weather without a wand.
Well, in a 'neglected naruto adopted by sannin fanfic', Naruto's character development would likely be very different. The Sannin are all extremely powerful and have their own areas of expertise. If Naruto was adopted by them, he'd be exposed to a whole new level of ninja training and knowledge. He'd probably grow up with more confidence, as he'd have the support and guidance of the Sannin. His relationships with other characters like Sasuke and Sakura might also change. For instance, instead of constantly trying to prove himself to everyone in the village, he could focus more on becoming a great ninja under the Sannin's tutelage and might have a more equal footing when interacting with his peers later on.
One possible plot twist could be that Naruto's unique way of raising the Sannin changes their personalities completely. For example, Jiraiya might become more reserved and studious under Naruto's influence. Another could be that the Sannin end up teaching Naruto secrets that were lost in the original timeline. Maybe Tsunade reveals a new form of medical ninjutsu that Naruto then uses to save many lives in future battles. Also, Orochimaru might turn away from his dark path earlier, leading to a different power structure in the shinobi world.
Well, one interesting concept could be the new abilities the characters might have. Maybe they develop unique jutsu that combine different elements in unexpected ways. Another could be the relationships between the new sannin, whether they have rivalries or strong bonds of friendship like the original sannin.