A more complex story could involve a dark force that threatens both worlds. Voldemort could team up with an evil warlock from Warcraft, and it's up to Harry Potter and his friends, along with some of the heroes from Warcraft, like Arthas before he turned evil, to stop them. This would require a lot of cooperation between the two groups, as they have to understand each other's cultures and magics to be successful.
One idea could be to have the wizards from Harry Potter visit Azeroth. They could learn about the different magic there, like shamanistic magic or the arcane magic used by mages in Warcraft. Maybe Harry could befriend a young orc shaman and together they discover new spells by combining their magical knowledge.
Another approach is to bring Warcraft characters to Hogwarts. Picture Thrall, the warchief, as a visiting lecturer on different forms of leadership. The Hogwarts students would be fascinated by his tales of uniting the orc clans. And the Warcraft magic users could compare their spells with those of the Hogwarts professors, leading to some interesting magical duels and exchanges.
One idea could be that the Hogwarts students are transported to Azeroth. They could learn magic from the Warcraft mages while also sharing their own spells. For example, Hermione might be fascinated by the arcane magic in Warcraft and try to find similarities with her own knowledge of magic. Another plot could involve Voldemort teaming up with an evil force from Warcraft to conquer both worlds. Harry and his friends would then have to gather allies from both universes to stop them.
Another option is a crossover with a different anime world, like Naruto. GT Goku could end up in the Hidden Leaf Village. The shinobi would be amazed by his power. Goku, being Goku, would be interested in learning their ninja techniques. They could team up against a common enemy that somehow has the ability to use both chakra and ki, creating a unique and exciting battle scenario.
One idea could be to focus on the characters' different abilities. Blade's vampire - hunting skills and the unique powers of the Underworld vampires could create some intense fight scenes. For example, Blade could team up with Selene from Underworld to take on a new, more powerful vampire threat that combines the worst aspects of both their worlds.
A more complex scenario could involve a group of witches who are at war in their own realm. They decide to bring some of the powerful Naruto characters into their world to fight on their behalf. Naruto and his friends would have to adapt to the strange magic - filled environment and the political intrigue of the witches' war.
One idea could be a crossover with the 'Lord of the Rings' universe. The Soul of Cinder could be a powerful entity that somehow ends up in Middle - earth. Maybe it's mistaken for a dark lord by some and has to prove its true nature. Another option is a crossover with 'Final Fantasy'. The Soul of Cinder's abilities could be translated into the magic and combat system of 'Final Fantasy', creating some really interesting battles.
Secondly, focus on the characters' interactions. If you have Hermione meet Jaina Proudmoore, think about how their different personalities and magical abilities would play off each other. Hermione's thirst for knowledge could lead to some great discussions with Jaina about arcane magic. Also, consider the cultural differences between the two worlds, like how orcs view honor compared to how wizards view good and evil.
One idea could be that Tinkerbell finds her way into the wizarding world of Harry Potter. Maybe she gets accidentally transported there by some magical mishap. She could use her fairy magic in Hogwarts, like helping to repair broken objects in a more sparkly and unique way compared to the Reparo charm.
One idea could be that the Avengers are somehow transported to the wizarding world. They might be initially confused by the magic but then start to work with the Hogwarts students and teachers to fight a common enemy, like a dark wizard who has also harnessed some sort of Muggle - like technology to become even more powerful. For example, Voldemort could team up with Hydra remnants to create a super - weapon that threatens both the magical and non - magical worlds.
A fun concept could be a Transylvanian wizard coming to Hogwarts as an exchange student. This wizard has a pet dragon that is different from the ones in the UK. He brings with him knowledge of Transylvanian magic, like how to use the power of the full moon in a different way than British wizards do, which intrigues Harry and his friends.
One idea could be that the characters from Riverdale somehow find themselves in the wizarding world of Harry Potter. Maybe Jughead could be a Muggle - born wizard who discovers his powers while at Hogwarts. He might write about his strange new experiences in his journal, just like he does in Riverdale.