One common theme is the clash of different worlds. Since it's a crossover, you often see the unique settings of each original work collide. For example, if it's a Durarara!! and Bungo Stray Dogs crossover, the normal yet chaotic Ikebukuro and the world full of gifted individuals with special abilities from Bungo Stray Dogs create a lot of interesting situations.
Character development is also a big theme. Writers like to take characters from different series and put them in new situations to see how they grow. In a Durarara!! and Naruto crossover, for instance, the Naruto characters might learn about the more modern and complex society of Ikebukuro, while the Durarara!! characters could be influenced by the ninja values of Naruto. This mutual influence leads to new aspects of their personalities emerging.
The theme of identity is often explored in durarara crossover fanfiction. For instance, when crossed with 'Psycho - Pass', the question of what defines a person in a society with strict moral evaluation (Psycho - Pass) and in the chaotic, diverse world of Durarara becomes a central point. Another common theme is the struggle for power. When combined with 'Attack on Titan', the fight for survival and power in both universes makes for a very engaging narrative.
One common theme is the clash of cultures. Since it's a crossover, different cultures from the FFXIV world and the other crossed - over world collide, which makes for interesting storylines.
One common theme is the clash of different powers. For example, when Venom crosses over with other superheroes or villains, there's always a comparison and sometimes a struggle between their abilities. Another theme is the exploration of new relationships. Like in crossovers with Spider - Man, it's about their complex relationship, whether they're enemies or allies at different points.
Often, there's a theme of friendship and cooperation. In crossovers like Boruto with the Attack on Titan world, Boruto and his friends have to work together with the characters from that world, like the Survey Corps. They learn from each other and grow stronger together. Also, a sense of discovery is common. Boruto and his team are often in a new world they don't understand, and they have to figure things out, which makes for an interesting read.
One common theme is the clash of different magic systems. For example, when Skyrim crosses over with a magical - based world like Harry Potter, you get to see how the Restoration magic in Skyrim compares to the spells in Hogwarts. Another theme is cultural differences. If Skyrim crosses with a world like Middle - earth, the Nordic culture clashes and sometimes blends with the cultures of elves and men in Middle - earth.
Another theme is the exploration of different universes. In many crossovers, Supergirl might find herself in a different universe where the rules are different. This allows for interesting plot developments as she has to adapt to new situations and new versions of familiar characters. It also gives a chance to explore what makes her character unique compared to others in different universes.
One common theme is the clash of cultures. Since it's a crossover, different worlds or time periods collide, and the musketeers have to adapt.
One common theme is power - how the characters from 'the breaker' interact with characters from other universes in terms of their powers. Another could be friendship. When different characters cross over, new friendships can form.
Another theme is power and its implications. Ciri has her own set of powers in her original story. When she crosses over, her powers may be different or interact in new ways with the powers in the new world. This can lead to her either being feared or revered, and she has to figure out how to handle this new status.
One common theme is the clash of different powers. For instance, when Ninjago characters cross over with characters from other universes like Power Rangers, their unique fighting styles and powers collide. It creates exciting battle scenes where they have to figure out how to work together despite their differences.