Maybe Sasuke teaches him the Chidori in a moment of camaraderie. And for the Rasengan, it could be an older and wiser Naruto from the future who travels back in time to teach his younger self.
In many fanfictions, Naruto might master the Rasengan through intense and unique training methods. Maybe he gets some special guidance from an unexpected source, like a hidden shinobi in the village who has a different perspective on chakra control. This person could show Naruto some new ways to focus his chakra, which finally enables him to form the Rasengan successfully.
In some fanfictions, Kakashi could also play a role. He is very knowledgeable and has seen the Rasengan in action. He might offer some tips on chakra control, which is crucial for Naruto to master the Rasengan.
Well, Tsunade could be a great helper. She has extensive knowledge of chakra control and medical ninjutsu. She could teach Naruto how to use his chakra more precisely when creating the Rasengan, perhaps by showing him some medical - ninjutsu - based chakra control techniques that can be applied. Minato, Naruto's father, could also play a role. He was the one who originally created the Rasengan. He could appear in Naruto's dreams or in some sort of time - travel scenario and show Naruto some hidden aspects of the Rasengan creation that he didn't know before. And then there's Sakura. She's become very strong over time. She could use her strength and knowledge to assist Naruto, maybe by creating some sort of training regimen for him to improve his Rasengan creation skills.
I'm not entirely sure specifically as 'annabeth' is often from the Percy Jackson series and 'rasengan' is from Naruto. It could be a fan - created story that combines elements of both universes in some way, perhaps with Annabeth somehow getting involved with the power or concept of the Rasengan.
Well, in some fanfics, Naruto might add elements to the Rasengan through intense training and experimentation. He could study different chakra natures and find ways to combine them with the Rasengan's basic form. For example, he might infuse lightning chakra into it to make it more piercing and fast - like a lightning - enhanced Rasengan.
Sakura. It would be really unexpected as she is mainly known for her medical ninjutsu and physical strength. But if she were to learn the Fire Rasengan, it could show a whole new side of her character. Maybe she'd incorporate her medical knowledge into the technique, like using it in a more precise and less destructive way.
No, Boruto is alive in the manga. The plot hasn't led to his death. However, the manga is ongoing, and anything could happen in the later developments.
The Naruto learns Rasengan fanfic can take the story in various directions. One direction could be a more in - depth exploration of the Rasengan's origin within the context of the fanfic. Another could be a time - travel plot where Naruto goes back in time and teaches his younger self how to learn Rasengan faster. It might also focus on the emotional turmoil Naruto goes through when he struggles to learn the jutsu, especially if he feels like he's letting down his village or his teacher Jiraiya.