One possible fanfiction could be about Naruto finding a sword that has a special connection to the Sage of Six Paths. Maybe the sword has the power to enhance his Rasengan or even cut through dimensions. It could also have a mind of its own and initially resist Naruto, but over time they form a bond.
Well, he could become even more powerful. Maybe he'd use it to defeat stronger enemies like Madara or Kaguya more easily. With a legendary weapon, his status as a hero in the village would be even more solid.
Well, he could become even more powerful. He might be able to defeat his enemies more easily, like taking on Akatsuki members with less effort. The legendary weapon could also give him new abilities or enhance his existing ones, such as making his Rasengan even stronger.
The Snakes, especially those related to Orochimaru's summons, are often used in fanfiction. They can bring an element of mystery and danger. Some fanfictions might explore the idea of a redeemed snake summon that helps Naruto in his quests, or a more powerful, ancient snake that was hidden away until now.
The use of legendary swords in Naruto fanfiction can also change the power dynamics between characters. A character who might not be as strong in the original series could become a formidable force with the aid of a powerful sword. Say, a side character gets hold of the Kubikiribocho and suddenly becomes a key player in battles, creating new and interesting storylines.
Perhaps it was a weapon created by a rogue ninja with unique powers. And for some reason, it found its way to Naruto in Wave. It might also be a weapon that was enchanted by a sorcerer long ago and has special abilities that Naruto will discover as he uses it.
One possible scenario in this fanfiction could be that Naruto's sister constantly interferes in his ninja training. She might think the training is too dangerous for him and tries to stop him from taking on challenging missions. For example, when Naruto is about to go on a mission to the Land of Waves, his sister could try to convince the Hokage not to send him, believing that he's not ready yet. This would add a whole new layer of conflict to the story, not just between Naruto and his sister, but also with the village's expectations of Naruto as a ninja.
A fanfiction about Naruto getting the Kusanagi could also involve a time - travel aspect. Naruto could be sent back in time and end up in the era when the Kusanagi was first created. There, he meets the original wielder and learns from them. He then brings the knowledge and the sword back to his own time, using it to defeat a great evil that was previously unbeatable.
In a Naruto fanfiction where he gets a massage, it could be a really interesting scenario. Maybe he's injured from a tough battle and the massage is part of his recovery. It could also be a way for him to relax after all the stress of being a ninja. This kind of fanfiction might explore his reaction to the gentle touch and care during the massage.