Well, it could be about Goku ending up in the One Piece world. Maybe he teams up with Luffy to fight a common enemy. For example, a powerful pirate who has some sort of dragon - like powers similar to the dragons in Dragon Ball. They would combine their unique fighting styles. Goku's energy blasts and Luffy's stretchy attacks would make for an epic showdown against the bad guy.
In this crossover fanfiction, perhaps there is a tournament in the One Piece world that attracts fighters from all over, including Goku. He enters to test his skills against new opponents. Luffy also joins in, thinking it's a great chance to show off his strength. Along the way, they discover that there is a dark force behind the tournament trying to steal the powers of the strong fighters. So they have to put aside their competitiveness and work together to stop this evil plot.
The plot might involve a search for the One Piece and the Dragon Balls at the same time. The Straw Hat crew and Goku's friends could be on this wild adventure together. Picture Zoro learning some ki - based sword techniques from Goku's friends, while Nami tries to figure out how to use the Dragon Balls to her advantage, like wishing for more gold or something. It would be a chaotic but exciting story full of unexpected twists.
In a crossover fanfiction, the Dragon Balls could be the key element. Suppose the One Piece characters learn about the Dragon Balls and their ability to grant wishes. Luffy would definitely want to use them to make some crazy wishes, like having an unlimited supply of meat. However, the villains from both universes also get wind of this. Frieza could team up with some of the powerful pirates like Blackbeard. This would force the heroes of both worlds to join forces. Goku and Luffy would lead their respective teams in a battle against this new, powerful alliance, with the fate of both universes at stake.
One possible plot could be that Goku and his friends somehow end up in the One Piece world. They meet Luffy and his crew. Goku might be interested in the Devil Fruits and their powers. Luffy, on the other hand, would be excited to see Goku's super strength and ki abilities. They could team up to fight a common enemy like a powerful pirate who has also acquired some sort of dragon ball - like artifacts. This would lead to an epic adventure with both the Saiyans' and the Straw Hats' unique fighting styles combined.
It could be a plot where Saitama meets Goku. Maybe they have a friendly sparring match at first. Goku would be excited to find someone so strong, while Saitama would be his usual nonchalant self. They might team up to face a new powerful villain that threatens both their universes.
Goku would probably be really excited to meet Luffy. He'd be curious about Luffy's rubber powers and would want to have a friendly sparring match right away. Luffy, on the other hand, would be in awe of Goku's strength and would see him as a great ally. He'd probably ask Goku to join his crew, but Goku would decline because he has his own friends and family in Dragon Ball world.
Well, perhaps the Saiyans in Dragon Ball Z detect the strong energy from the Devil Fruits in One Piece. Vegeta decides to visit the One Piece world to see if he can gain an edge over Goku. Meanwhile, the Straw Hats are dealing with a new threat that seems to be more powerful than any they've faced before. Vegeta initially clashes with the Straw Hats but then realizes they need to work together. They combine their skills, like Goku's Kamehameha and Luffy's Gear Fourth, to take on the big bad.
One possible plot could be that Luffy and his crew are sailing in the Grand Line when they encounter a strange energy. It turns out to be a Dragon Ball. They then have to deal with various villains from both universes trying to get the ball. Maybe Frieza hears about it and teams up with some of the pirates from One Piece. And Goku, sensing the power of the Dragon Ball, also arrives in the One Piece world to help Luffy protect it.
The plot might involve a tournament where characters from both Naruto and Dragon Ball Super participate. Naruto's friends like Sasuke and Sakura could join in, and so could Goku's friends like Vegeta and Piccolo. The tournament could have unique rules that combine the elements of both worlds. For example, in addition to physical combat, there could be challenges related to chakra control and ki manipulation. The story could also explore the relationships between the characters from different universes, like how Naruto and Vegeta might initially clash due to their headstrong personalities but later come to respect each other.
It's likely Goku. His Super Saiyan forms give him incredible power levels that far exceed most of the characters in One Piece. He can move at incredible speeds, has amazing strength, and can fire powerful energy blasts. Even Luffy in his Gear Fifth form would probably have a hard time against Goku at his full power.
It would be a wild crossover. The art styles of the two series are different, but in fanfiction, that could add to the charm. Dragon Ball Z has its more detailed and anime - esque style, while One Punch Man has a simpler yet impactful look. In the story, the characters could visit each other's worlds. Goku could explore the city where Saitama lives and be baffled by the normalcy of it all compared to his battles against Frieza and Cell. Saitama could also be introduced to the Dragon Balls and their wish - granting powers, which might pique his interest.
Well, it might start with Naruto somehow ending up in the One Piece world. He could be mistaken for a strange new type of Devil Fruit user. His goal could be to find a way back home, but in the process, he gets involved in the Straw Hat crew's adventures. They might encounter a villain who is after Naruto's chakra and Luffy's Gum - Gum powers, leading to an epic battle where they have to combine their skills to win.