There's a possibility that it's a spirit or a deity in the world of bending. This entity is impressed by Naruto's tenacity and chooses to guide him on his journey of learning bending.
The fanfiction might be about Naruto accidentally stumbling upon a ancient scroll that contains the secrets of bending. He decides to learn it out of curiosity. He begins with fire bending, which is a challenge as it's very different from his chakra - based fire techniques. But with his ninja training and unwavering will, he manages to figure out how to control the flames in the new way of bending.
At first, his friends would be shocked. Hermione might think it's some kind of dark magic at first glance. But as Harry shows them what he can do, she would start to analyze it scientifically. Ron would be more awed. He'd be like a kid seeing a new cool trick. They would both support Harry in exploring this new ability, but also be a bit cautious as they don't fully understand where it comes from or what the implications are in their wizarding world.
He might learn a time - traveling jutsu. This would be really cool as it could allow him to go back and change certain events in the Naruto world, or gain knowledge from the past to use in the present battles.
One interesting concept could be the combination of Naruto's ninja skills with bending abilities. For example, Naruto might use his chakra control to enhance his bending, creating unique and powerful attacks. Another concept could be the interaction between Naruto characters and the bending world's elements. It could lead to new storylines and character developments.
First, you need to have a clear idea of the new bloodline ability. Decide what it can do, like if it's a form of energy bending or something more unique like bending emotions. Then, think about how it fits into the existing Naruto world. You also need to create a character who has this bloodline. Give them a backstory that explains how they discovered or developed their powers.
One possible scenario in this fanfiction could be that Naruto, being banished from his village, stumbles upon a magical realm. There, he might meet a mentor who teaches him magic. This could lead to him developing new powers and a whole new identity, different from the ninja he once was. It could also open up opportunities for crossovers with other magical universes in the fanfiction world.
In fanfiction, Naruto learning the Vacuum Jutsu could be really cool. It might give him a new and powerful offensive technique. Maybe he'd learn it from an unexpected source, like an old hermit in a forgotten land. This could potentially change the power dynamics in battles he's in.
Sakura could be the one teaching him. She's known for being intelligent and having good domestic skills. She might start by showing Naruto the basics in the kitchen, like how to hold a knife properly and how to chop vegetables evenly.
A traveling nen master could be Naruto's mentor. This master could be on a journey to spread the knowledge of nen. He crosses paths with Naruto and decides to teach him. The master might have a strict teaching style, pushing Naruto to his limits, but also guiding him carefully through the complex world of nen.