Another idea is to make an OC that is a part of a secret organization within the Naruto world that has its own motives and goals. This OC could be initially working against the main characters but later realize that their goals align in some ways, leading to complex relationships and plot twists.
You could also have an OC with a unique ninja ability that no one has seen before in the Naruto universe. Maybe an ability to control time on a small scale, like being able to slow down time for a few seconds during a battle. This would make the OC stand out and add new dynamics to the battles in the fanfiction.
One idea could be creating an OC who is a long - lost relative of a major Naruto character. For example, an OC who is related to Sasuke but was raised in a different village. This could lead to interesting storylines of self - discovery and loyalty conflicts.
One interesting idea could be the concept of an immortal OC (original character) interacting with the well - established Naruto universe. For example, their immortality might lead to unique relationships with the mortal characters. They could have witnessed countless historical events in the Naruto world and thus possess a wealth of knowledge that others don't. This could potentially change the course of the story as they might use this knowledge to influence the actions of the main characters like Naruto or Sasuke.
You could do a crossover with a post - apocalyptic world. Naruto characters find themselves in a world full of ruins and new threats. The oc could be a survivor from that world who teaches the Naruto characters new survival skills, and in return, the Naruto characters teach the oc about chakra and ninjutsu.
Define their goals. Do they want to be the strongest ninja? Or are they more interested in peace - building? Their goals will drive their actions throughout the fanfiction. Also, give them flaws. Maybe they are too impulsive or overly trusting. Flaws make the character more relatable and human.
The OC could be a descendant of a powerful clan that was thought to be extinct. Their presence in the Naruto world stirs up interest among many characters. The OC's knowledge of ancient jutsu and their kind heart draw in characters like Kakashi, Shikamaru, etc. into a harem. The OC then has to navigate the complex relationships while also trying to keep their clan's secrets safe.
One idea could be that the OC, reborn as Naruto, uses their prior knowledge to quickly master jutsu. For example, they might know about the Rasengan from the start and be able to perfect it faster. Another plot could involve the OC changing the relationships in the village. Maybe they befriend Sasuke earlier and prevent his defection. Or they could introduce new ninja techniques from their past life to the Hidden Leaf.
One idea could be that the OC team is on a mission to retrieve a rare and powerful ninja artifact that has been lost for centuries. This could lead to battles with other ninja clans who also want the artifact.
Another plot could involve an OC reborn into the body of a criminal in the Naruto world. They have to struggle to redeem themselves and prove that they are not the same person as the original criminal. Along the way, they could discover the real reasons behind the original criminal's actions and try to right the wrongs that were committed.
One idea could be an OC who is a time - traveler from the future. They come back to the Naruto world to prevent a great disaster that they know will occur in the future. This OC could have unique powers related to time manipulation or future - sight.
One idea could be an OC Hatake who has a unique chakra ability. For example, they can manipulate ice in a way that's different from Haku. They could use this to create ice sculptures that come to life in battle. Another plot could involve the OC Hatake being a long - lost relative of Kakashi. This would bring in a lot of family - related drama and secrets to uncover. A third idea is that the OC Hatake has a special bond with animals, like being able to communicate with wolves, which is rare in the Naruto universe.
One idea could be an OC Senju who has a unique ability related to plant manipulation, like being able to make plants grow rapidly into defensive or offensive structures. Another could be an OC Senju who is a healer and has to deal with the aftermath of a big battle in the Naruto world. Maybe an OC Senju who is on a quest to discover a long - lost Senju clan jutsu that was forgotten over time.