A possible plot could involve a character from the RWBY world, like Ruby, going to the Harry Potter universe. She could be amazed by the magic there and try to learn some spells. Meanwhile, the Hogwarts students could be intrigued by her unique weapon and combat skills. This exchange of knowledge and skills could lead to an interesting story where they team up to face a common enemy that somehow threatens both worlds.
Maybe a magical artifact from the Harry Potter universe finds its way into the RWBY world. This causes chaos as both sides try to figure out what it is and how to control it. The RWBY teams might initially be suspicious of the magic from Harry Potter's world, but as they see the potential benefits, they start to work together with the Harry Potter characters to harness the power of the artifact for the greater good.
One idea could be that Harry Potter and his friends accidentally get transported to the RWBY world. They could then use their magic in unique ways to help the RWBY characters fight Grimm. For example, Hermione could use her knowledge of spells to create new defenses against the Grimm that the RWBY characters haven't thought of before.
A really cool plot could be that Voldemort somehow follows Harry into the RWBY world. This would force the RWBY characters and Harry to team up against this new and powerful threat. Harry would have to teach the RWBY crew about the nature of Voldemort and his Horcruxes, while the RWBY team would introduce Harry to the ways of fighting Grimm and using Dust. It would be a clash of two very different magical systems and a great opportunity for character development and epic battles.
One idea could be that the actors from the Harry Potter movies get magically transported into the wizarding world of Harry Potter. They could use their knowledge of the story to help the characters, or they could be completely bewildered and cause chaos. For example, Daniel Radcliffe could end up having to explain to Harry Potter himself how his story is told in the Muggle world.
In 'immortal harry potter rwby fanfiction', a great plot could be about Harry being the key to unlocking an ancient power in Remnant. Since he's immortal, he has had more time to study magic and ancient lore. He discovers that there are hidden magical energies in Remnant that are similar to those in the wizarding world. With the help of the RWBY gang, he tries to harness this power to defeat Salem once and for all. This would involve a lot of exploration of both the magical and non - magical aspects of Remnant, and the RWBY characters would be learning a great deal from Harry about magic and its potential uses.
One idea could be the different combat styles of RWBY and STRQ teams clashing and then learning from each other. For example, Ruby's speed might be something the older STRQ members could be impressed by and give her some pointers based on their more experienced fighting. Another plot idea could be exploring the relationships between the characters from both groups. Maybe Weiss could form a bond with one of the STRQ members over their shared love for music, if that's part of their backstory. It could also involve a common enemy that forces them to work together and in the process, they discover secrets about their respective teams.
One idea could be that Harry discovers Narcissa has a secret mission to undermine Voldemort from within. Maybe she's been secretly helping the Order of the Phoenix all along and Harry stumbles upon this knowledge.
In a 'Harry Potter meets Tom Riddle' fanfiction, a really unique plot could be that Tom Riddle is reborn as a normal wizard without the dark desires due to some powerful magic. Harry Potter meets this new Tom and they become friends at Hogwarts. However, there are still some remnants of the old Tom's power that attract dark forces. So, Harry and Tom have to work together to fend off these threats while also exploring Tom's new identity and how it affects the future of the wizarding world. This would involve a lot of character development for both Harry and Tom, as they navigate their relationship in this new scenario.
A plot could revolve around a magical artifact that has been stolen from Hogwarts. Harry and Pansy are the prime suspects in each other's eyes. But as they start to investigate, they realize they are being framed. They then team up to find the real thief. Along the way, they discover that they have more in common than they thought, like their love for Hogwarts in their own ways. As they search through the dark corners of the castle and the Forbidden Forest, their relationship evolves from animosity to respect.
In a 'Harry Potter meets Sirius Black fanfiction', it could be interesting if Sirius and Harry found a way to time - travel. They could go back to the time when James and Lily were alive. This would not only allow Harry to meet his parents but also give Sirius a chance to change some events that led to his downfall. They might also interfere with the actions of Voldemort in the past, creating a whole new timeline and a different future for the wizarding world.
Well, perhaps the female Harry Potter is transported to the RWBY world due to a magical accident. In this new world, she realizes that the concept of magic is different but still has some similarities. She could start a school of magic in the RWBY world, teaching students both magic spells and the values she learned at Hogwarts. Her presence might also attract the attention of some of the more shadowy organizations in RWBY, who see her magic as a powerful tool to be either controlled or destroyed.
One idea could be a crossover where the RWBY characters are transported to a different Rooster Teeth universe and have to team up with the local heroes to defeat a common enemy. For example, they could end up in the world of 'Red vs Blue' and have to deal with the chaotic military situations there.