Well, in some Naruto Revenge One Piece fanfictions, Naruto might be reborn in the One Piece world with all his memories intact. He could be on a revenge mission against a powerful organization that has a connection to his past life's enemies. Maybe they are trying to collect the same kind of power sources that were coveted in the Naruto world. And he uses his ninja skills along with the unique abilities of the One Piece world like Haki and Devil Fruits to get his revenge. Another example could be a story where a character from One Piece travels to the Naruto world, angers Naruto, and then Naruto chases him back to the One Piece world for revenge, causing all sorts of chaos and new alliances along the way.
In a fanfiction where Naruto is a fishman in One Piece, Naruto would face new challenges. For example, dealing with the discrimination that some fishmen face in the One Piece world. But he'd also have new opportunities. He could use his fishman physiology to swim faster and deeper, discover hidden treasures, and maybe even find a way to connect the ninja world with the pirate world. His Nine - Tailed Fox chakra might also have some interesting interactions with the strange powers in One Piece.
Well, to blend the two universes in a Naruto Revenge One Piece fanfic, one way is through the idea of a shared threat. Suppose there is a powerful entity that has been causing problems in both the Naruto and One Piece worlds. Naruto, with his ninja skills and determination, enters the One Piece world to team up with the local heroes like Luffy and his crew. His sharingan, if he has it, could be seen as a similar power to some of the more mysterious One Piece abilities. The cultures of the two worlds could also mix. For instance, the shinobi villages in Naruto could have a parallel in the different islands and factions in One Piece. And Naruto could use his knowledge of shinobi tactics and combine it with the sea - faring and combat knowledge of the One Piece characters to take revenge on the shared threat.
A Naruto - One Piece fanfiction could explore the differences in their power systems. While Naruto has chakra-based abilities, the pirates in One Piece rely on Haki, Devil Fruits, and physical strength. It would be fascinating to see how Naruto would interact with the various characters in the One Piece universe. For example, how would he get along with Zoro, the swordsman? Or how would he deal with the wily Nami when it comes to treasure? There are so many possibilities for an exciting and unique story.
Naruto could fit in by using his physical abilities. His superhuman strength, speed, and endurance, which he developed through his ninja training, would make him a formidable opponent in the One Piece world. He could easily take on weaker pirates or even some of the lower - level Marines.
Immortality in Naruto - One Piece fanfiction can also bring in elements of loneliness. The character might have seen all their friends and allies die over time. They could then be on a quest to find a way to end their immortality. Or, they might use their eternal existence to preserve the values of both worlds, acting as a sort of guardian. They could form alliances with different groups in Naruto and One Piece universes, based on their long - term view of what's good for the overall balance.
There are many interesting fanfictions that combine Naruto and One Piece with a captain - like character. In some, the captain might be a character who has abilities similar to those in both Naruto and One Piece worlds. For example, they could have the power of chakra like in Naruto and also use Haki like in One Piece. These fanfictions often explore unique storylines, such as a quest to find a special treasure that can only be unlocked with both Naruto - style ninjutsu and One Piece - style devil fruit powers.
One idea could be a fanfiction where a captain from One Piece accidentally sails into the Naruto world. He then decides to recruit some of the powerful ninja as part of his crew. This could lead to some really interesting dynamics as the ninja have to adjust to life on a ship and the rules of the One Piece world.
In Naruto fanfiction, if Sakura were to poison someone, it could be a very dark and interesting plot twist. Maybe she's been pushed to the edge and decides to use poison as a form of revenge. In One Piece fanfiction, the concept of Sakura poisoning someone is a crossover idea that might not fit the normal One Piece world directly. But if we consider it in a creative sense, perhaps she could be a new and unexpected villain in a strange new island arc.
The Black Pearl could be a treasure in the One Piece world that somehow ends up in the Naruto world. This could cause chaos as the shinobi are not used to such a valuable and strange object. Pirates from One Piece might then travel to the Naruto world to retrieve it, leading to all sorts of interesting interactions between the two groups.