In a Harry Potter and LOTR crossover fanfiction, black magic could take on different forms. In the Harry Potter universe, it's often associated with the Dark Arts like the Unforgivable Curses. In LOTR, dark magic is related to Sauron and his minions. A crossover might explore how wizards from Harry Potter's world react to the more ancient and malevolent black magic of Middle - earth.
Well, imagine that the One Ring has a strange connection to the chakra in Naruto's world. The Fellowship discovers that Naruto has a unique ability to resist the ring's power due to his strong will and chakra control. So they ask for his help in destroying the ring. Along the way, Naruto teaches the hobbits some basic self - defense ninja moves.
A really cool aspect of a Percy Jackson and LOTR crossover fanfiction could be the character interactions. Annabeth, with her strategic mind, could collaborate with Gandalf. She might learn a great deal from his wisdom and long - experience in Middle - earth. On the other hand, Legolas could be fascinated by the archery skills of the Apollo - related demigods. The cultural differences between the two worlds would also add depth to the story. The demigods, coming from a modern - ish world (compared to Middle - earth) would have different values and ways of thinking, which could lead to both conflicts and growth for the characters involved.
One possible plot could be that Naruto and his friends are somehow transported to Middle - earth. Naruto, with his never - give - up attitude, could inspire the hobbits on their journey. Maybe Naruto's chakra could be seen as a new form of magic in Middle - earth. His shadow clones could be used to confuse the orcs, just like how they confuse his enemies in the Naruto world. And the characters from LotR could learn about the concept of ninja and their unique skills from Naruto and his comrades.
One interesting storyline could be the Federation from Star Trek discovers the world of Middle - earth from Lotr. Maybe they try to introduce their advanced technology to the Middle - earthlings. For example, they could offer medical help to the injured during battles. Another could be characters from both universes teaming up to fight a common enemy, like a powerful dark entity that threatens both the Federation's space and Middle - earth.
Well, perhaps Eragon's dragon, Saphira, is injured and they have to seek out the healing magic in Skyrim. Along the way, they meet the Dragonborn. The two dragon - related characters could either become friends or rivals. Eragon might be amazed at the variety of dragons in Skyrim, some of which are different from the ones he knows. And he could share his knowledge of dragon - riding with the Dragonborn.
One idea could be that Percy and his friends are on a quest and accidentally stumble into Alagaesia, the world of Eragon. There, they meet Eragon and Saphira. The demigods' powers might be seen as strange magic by the people of Alagaesia. Percy could use his water - controlling abilities to help Eragon in a battle against some new threat that is both a danger to the demigods' world and Alagaesia, like a powerful water - based demon. They would have to learn to work together, with Percy teaching Eragon about the modern world's concepts and Eragon showing Percy the ways of magic in his world.
One possible plot could be that Eragon somehow gets transported to Middle - earth. He could meet Aragorn and learn from his leadership skills. Maybe they would join forces to fight a common enemy like a new breed of dark creatures created by a combination of Sauron's magic and the dark forces from Eragon's world.
In a crossover fanfiction, black magic might be the catalyst for the meeting of the two worlds. Maybe a dark sorcerer in Middle - earth uses black magic to open a portal to the wizarding world of Harry Potter. This would bring about chaos as the characters from both sides have to deal with this new and unfamiliar form of black magic. The wizards from Hogwarts may be shocked at the more primal and ancient black magic they encounter in Middle - earth.
One plot idea could be that the One Ring somehow finds its way into the X - Men universe. Maybe Magneto senses its power and wants to use it for his own purposes, believing it could give him ultimate control over mutants and humans alike. The X - Men, on the other hand, realize the danger of the Ring and try to stop Magneto from getting his hands on it. Another idea is that some of the LOTR characters are reincarnated as mutants. For example, Aragorn could be a mutant with enhanced leadership abilities and physical prowess, and he teams up with the X - Men to fight a common enemy that threatens both Middle - earth and the mutant world.