In Naruto fanfictions, Raiton Affinity usually means a character has a natural inclination towards using lightning - based jutsu. It can be shown as an easier time learning Raiton techniques or having more powerful Raiton attacks.
One good Naruto Raiton Affinity fanfiction is 'The Raiton Prodigy'. It focuses on a character with a strong Raiton affinity and their journey to master it. Another is 'Raiton's Edge' which has some really cool battles involving Raiton techniques.
I think Sasuke could be a great main character. He already has an affinity for lightning - based attacks. In a fanfiction, he could further develop his Raiton skills and become an even more powerful Raiton master. He could use his new - found skills to seek revenge in a different way or to protect the village in a more unique manner.
Perhaps the story could revolve around a Raiton master who has lost their memory. As they journey through the Naruto world, they start to regain bits of their past while also teaching others about Raiton techniques. They might have a special connection to a long - lost Raiton - based jutsu that could change the balance of power in the ninja world.
A 'Solar - Flare Rasengan'. Naruto could combine his wind - style chakra with some kind of solar - based energy he discovers. This jutsu would be like a super - charged Rasengan that emits a blinding light as well as powerful wind - based damage.
There could be a jutsu that allows for instant teleportation across long distances. This jutsu might be a new discovery in the fanfiction world, perhaps created by a character who has been experimenting with space - time ninjutsu. They might use it to quickly get in and out of battles or reach far - off places in a blink.
It could be a new form of Rasengan. Maybe Naruto discovers a way to combine different elements with the Rasengan more effectively, like adding lightning to it for a more powerful and faster attack.
There's also the 'Inferno Storm Jutsu' in some fanfictions. It creates a large - scale storm made entirely of fire. The fire in this storm has different intensities, with the center being the hottest and most destructive. It can cover a large area, making it a great offensive move against groups of enemies.
Maybe Sasuke. Although they are rivals, they also have a deep bond. Sasuke might have come across a unique jutsu during his travels and decide to teach it to Naruto so that they can both become stronger and better protect their village.
It could be Naruto himself who discovers and uses the Katon Hijingakure no Jutsu in the fanfiction. Since he's always exploring new jutsus and pushing his limits.