Here's another plot twist. The Fountain of Youth in the Pirates of the Caribbean world is actually a creation of a minor Greek god from the Percy Jackson world. This god was trying to create a new power source but lost control of it. Now, both the pirates and the demigods are after it for different reasons. The pirates want eternal youth, while the demigods want to stop it from causing chaos in both worlds.
If we think about it, Percy could use his ability to communicate with sea creatures to help the pirates. For instance, he could ask the dolphins to lead the ship to a safe place or warn them about incoming danger. The pirates would be amazed by this. Meanwhile, the demigods would be shocked by the pirates' lack of knowledge about the Greek gods but also impressed by their sailing skills and their ability to survive in a cut - throat world. The interactions would be full of misunderstandings at first but could grow into mutual respect as they face challenges together.
One good crossover could be Percy using his water - controlling abilities in the world of Pirates of the Caribbean. For example, he could help Jack Sparrow's ship escape from a powerful maelstrom by calming the waters. Another idea is Percy teaming up with the pirates to fight against a common sea - based enemy, like a giant sea monster that威胁 both the demigod world and the pirate world.
A great plot twist could be that they end up having to team up instead of fight. Maybe there's a greater evil that combines elements of Greek and Egyptian mythology that they can only defeat together. Their powers could combine in unexpected ways, like Percy's water powers being able to enhance Carter's magic related to the Nile.
One way to combine the two universes could be through a portal. Imagine Percy Jackson accidentally stumbling upon a magical portal while on a quest near the ocean. This portal leads him to the world of Pirates of the Caribbean. He could then team up with Jack Sparrow, using his demigod powers to help Jack in his adventures, like fighting Davy Jones' crew. Maybe Percy's ability to control water could be a great asset during sea battles.
One interesting plot could be that Naruto, with his ability to use chakra and perform ninjutsu, somehow ends up in the world of Pirates of the Caribbean. He might team up with Jack Sparrow. Naruto's speed and strength could help them in their sea adventures and battles against the cursed pirates or sea monsters. For example, he could use his Rasengan to break through the defenses of some powerful pirate ships or fight off the kraken-like creatures with his shadow clone jutsu.
Harry Potter could be a great addition. He could use his magic to help or hinder the pirates. Maybe he gets accidentally transported to the Caribbean and has to figure out how to get back home while dealing with the likes of Captain Jack Sparrow.
There might be a fanfiction plot where Elizabeth Swann, instead of being a damsel in distress at times, becomes a powerful pirate captain in her own right. She could lead her own ship and crew, and have adventures that cross paths with Jack Sparrow's. For example, she might be on a quest to find a magical artifact that can control the seas and has to outwit other pirates and sea monsters to get it.
Well, perhaps in this fanfic, the glass slipper is actually a magical artifact from the Greek mythology world. Cinderella's father was a demigod who hid the slipper for her to find when she was ready. The twist could be that instead of a fairy godmother, it's a satyr who helps her get to the ball. Percy Jackson gets involved when he realizes that the slipper has the power to open a portal to a dangerous place in the Underworld and he needs Cinderella's help to stop it from falling into the wrong hands.
The plot often involves a search for treasure. Pirates sail the dangerous seas, face other pirates and sea monsters while trying to find hidden gold.
Another plot could involve Elizabeth Swann time - traveling. She gets sent to a future version of the Caribbean where piracy has been completely eradicated. However, she discovers that without pirates, the balance of power in the region has been thrown off and there are new tyrannical forces at play. So, she has to find a way to bring back the spirit of piracy in a more civilized way to restore the balance. She uses her knowledge from the past and her wits to start a revolution of sorts.