A time - travel fanfiction could be interesting too. Suppose a character from the future (maybe a descendant of one of the main characters) travels back in time to the era of Naruto. They could have knowledge of future events and try to change things for the better, or they could be there to witness the great events and heroes of that time first - hand. This type of story allows for a lot of interaction between the new character and the existing Naruto cast, and can lead to some really exciting plot twists.
Another idea is to write a fanfiction set in an alternate universe. For example, what if Naruto was raised by a different person? Maybe by Iruka instead of being alone as a child. You could explore how this different upbringing would change his personality and his relationships with others. This gives you a lot of room to be creative and put your own spin on the Naruto universe.
Next, start writing the first chapter. Don't worry too much about making it perfect at first. Just get your ideas down on paper (or on the screen). You can always go back and edit later. Try to capture the tone of the Naruto series. It's often action - packed, but also has a lot of heart and friendship themes. So, include some exciting fight scenes and also some emotional moments between characters.
One idea could be a time - travel plot. Your brother's favorite character from Naruto, say Naruto himself, travels back in time to prevent a great tragedy that was about to befall the Hidden Leaf Village. Another plot could be a 'what - if' scenario. For example, what if Sasuke never left the village? You could explore how the relationships between the characters would develop differently. A third idea might be a crossover plot, like Naruto characters meeting characters from another anime world, but still keeping the essence of Naruto's universe intact.
For beginners, 'Naruto: The First Mission' is a good start. It's a short and simple fanfic that follows Naruto on his very first real mission outside of the village. It gives a good sense of the Naruto world and the basic ninja concepts without being too complex.
A great idea for a 'control naruto fanfiction' is to have Naruto under the control of a time - traveling villain who wants to change the future of the ninja world by using Naruto's power. Or, Naruto could be controlled by a curse that forces him to perform certain tasks against his will. Also, consider a story where Naruto is controlled by a powerful psychic who wants to use him to take over all the ninja villages.
One idea could be a Naruto in a different world setting, like a modern - day Earth where he has to hide his ninja skills. Another could be a story where Naruto teams up with characters from other anime to fight a common enemy. Also, a fanfic about Naruto's training journey in a new and mysterious land would be interesting.
A more complex fanfiction could involve a threat that endangers both the Naruto universe and the world of Sofia the First. So, Naruto and Sofia have to team up along with their respective friends. Naruto's friends like Sasuke and Sakura could join forces with Sofia's friends like Amber and James. They would all need to combine their different skills and abilities to defeat this common enemy.
Another aspect could be his relationships. He might have had a mentor who was initially skeptical of his abilities because he didn't come from a well - known shinobi family. But through hard work and determination, he won the mentor over. And perhaps he had a love interest in a female shinobi from a rival village, which added a layer of complexity to his story.
One idea could be a story where Naruto discovers a hidden nano - technology in the Hidden Leaf Village that was left by an ancient shinobi. This tech gives him new powers to fight enemies.
One interesting plot idea could be a time - travel story. For example, Naruto is sent back in time to the era of the First Hokage. He could use his knowledge of future jutsu and events to change things for the better in the past. Another idea is a story where Naruto discovers a hidden clan within Konoha that has a unique and powerful Kekkei Genkai. He then has to help this clan gain acceptance in the village. A third idea might be a story where Naruto is turned into a different creature, like a cat or a fox, and has to find a way to turn back while still dealing with the normal threats to the village.
One interesting idea could be the combination of Naruto's ninja skills with mecha technology. For example, Naruto might use his chakra to power up the mecha in unique ways. Another idea could be the new enemies that are created specifically for this mecha - Naruto concept, like robotic shinobi that require different combat strategies compared to normal foes. Also, the design of the mecha Naruto itself can be really cool, perhaps with features inspired by the Nine - Tails.