Another way is by having them meet due to a magical accident. Maybe a spell gone wrong transports Tauriel to Hogwarts or vice versa. Then they have to figure out how to get Tauriel back to her world while also dealing with the chaos that such an event causes in the wizarding world. It would be a story full of misunderstandings at first and then growing friendship and cooperation.
They can be blended through a shared adventure. For example, they could be on a quest to find a powerful magical item that has significance in both the wizarding world and Tauriel's elven realm. This would force them to work together and use their respective skills, like Harry's spell - casting and Tauriel's combat abilities.
Another aspect to blend their characters is their backstories. Harry's tragic past with his parents' death and his fight against Voldemort can be paralleled with Emma's own complex history in the mutant world. Fanfiction writers could explore how these past experiences shape their actions when they meet. Maybe Harry's sense of justice is strengthened by Emma's own experiences of fighting for mutant rights, and they decide to create a new world order where both mutants and wizards can co - exist peacefully.
A good way is to focus on their shared traits. Both Harry and Daryl are survivors. Harry has survived Voldemort's attacks and Daryl has survived the zombie apocalypse. So, in fanfiction, they can bond over their experiences of facing tough odds. For instance, they could exchange stories of loss and how they overcame it.
Well, you could start by having Christian Grey's personality traits influence a character in the Harry Potter universe. For example, if a Hogwarts student was suddenly infused with Christian Grey's confidence and assertiveness, it would change their interactions with others. They might be more bold in asking professors for favors or standing up to bullies like Draco Malfoy.
Well, you can start by finding common traits. Both are young leaders in their own ways. Harry leads his friends at Hogwarts in their battles against Voldemort, and Ciel leads his servants in his fight against those who wronged him. So, a story could be built around them sharing leadership strategies.
One way is through character creation. For example, a new character could be based on a Norse god or goddess, with their powers and personalities reflected in the Harry Potter world. So, like a character inspired by Thor could have the power of lightning in the magical context of Hogwarts.
The worlds can be blended by having Barbie visit Diagon Alley. She could be amazed by all the magical items and use her fashion sense to customize her wizarding robes. For instance, adding some sparkly elements that are typical of Barbie's style.
The blend can occur through the use of magic in relation to trigonometry in solving problems. For example, in a fanfiction, a magical creature is lost in a forest that is magically generated with trigonometric patterns. The characters need to use their knowledge of both magic and trigonometry to find the creature. Also, a character's magical power could be related to their understanding of trigonometry, so as they learn more math, their magic becomes stronger and more versatile.
The theme of sacrifice is present in both. In Harry Potter, Harry sacrifices himself to save the wizarding world. In Ender's Game, Ender sacrifices his childhood for the sake of humanity. In fanfiction, this could be explored further. Maybe a character from Harry Potter has to sacrifice something in the Ender's Game universe to achieve a greater good. The theme of friendship is also key. Harry has Ron and Hermione, and Ender has his friends at Battle School. Fanfiction could show how these different friendship dynamics interact when the two worlds meet.
A simple way is to have Bruce Banner be a Muggleborn in the Harry Potter world. This would allow for his character to be integrated into the story more easily. The slash aspect could involve a relationship with Harry Potter himself. They could bond over their shared experiences of feeling different from others. Harry as a wizard with a unique past and Banner as a scientist with a big secret (the Hulk).
Well, often in such fanfiction, the magic systems are combined. For example, spells from Harry Potter like 'Expelliarmus' might be used in the Skyrim setting. Writers might have a character who is a wizard from Hogwarts suddenly find themselves in Skyrim and use their magic there. It creates a really interesting crossover where the different rules and powers of each magic world collide.