Another approach is to have characters from one universe cross over to the other. Maybe Darth Vader could end up in Gotham. His imposing presence and dark powers would be a huge shock to the criminals there. He could even form an unlikely alliance with Batman, with Vader's goal being to find a way back to his own universe while Batman tries to keep Gotham safe from this new, extremely powerful threat.
One way to merge the two universes in fanfiction could be through a plot device like a dimensional rift. For example, a Sith Lord could accidentally open a rift that leads to Gotham City. This would bring the dark and brooding atmosphere of The Dark Knight into the Star Wars universe. Batman might find himself in a world of lightsabers and the Force, and his detective skills could be put to the test in a whole new way.
In fanfiction, it could also be interesting to explore how the concepts of the Force and the Dark Side compare to the morality in Gotham. The Jedi's code of honor could be contrasted with Batman's no - killing rule. A character like Luke Skywalker could come to Gotham and try to inspire the people there with his Jedi teachings, while also learning from Batman about how to fight crime in a more 'grounded' way.
It could be Naruto himself. His ability to tap into the Nine - Tails' chakra gives him an incredible power boost. In the merged universe, he might be able to use the Force as well, which would make him an unstoppable force. With his speed, strength, and now potentially the power of the Force, he could easily defeat most opponents.
However, some might argue that Levi Ackerman could hold his own. His incredible speed and combat proficiency with blades could potentially make him a match for some of the Star Wars characters. If he were to get his hands on a lightsaber, he might become an even greater threat. But in the grand scheme of things, when facing the more powerful Force - using characters, he might still be at a disadvantage.
One way could be through a magical portal. Imagine in a fanfic, a powerful mage in the Game of Thrones world accidentally opens a portal to the Naruto universe. Dark Naruto, with his edgy and powerful nature, could be seen as a threat similar to some of the dark forces in Game of Thrones. He might form an alliance with a power - hungry lord in Westeros, thinking he can use their resources to achieve his own goals in the Naruto world. For example, if he teams up with Littlefinger, they could plot to take over both kingdoms using Dark Naruto's powers and Littlefinger's cunning.
Power and its corrupting influence is another theme. The Emperor's thirst for power in Star Wars and the various power - hungry criminals in Gotham. Fanfiction might explore how characters from one universe would react to the power dynamics in the other. For example, would Batman be able to resist the allure of the Dark Side if he were exposed to the Force?
In a Naruto x Star Wars Rebels fanfic, the two universes could be merged by exploring the idea of different cultures. The diverse cultures in Naruto, like the Hidden Villages, could be compared to the various planets and species in Star Wars. For instance, the Hidden Leaf Village could be seen as a planet in the Star Wars universe. The values and traditions of each could be shared. The Rebels' fight for freedom could be paralleled with the ninja's fight for their villages. This would allow for a deeper exploration of themes such as loyalty, friendship, and the struggle against oppression in both universes as the characters from Naruto and Star Wars Rebels interact and influence each other.
In fanfiction, they often merge through the concept of interdimensional travel. For example, a portal might open that transports the Transformers to the Star Wars galaxy. Then, they start interacting with the different species and factions there.
Another approach could be a shared enemy. Suppose there is an entity that exists in both universes in a different form. Writers could create a story where the characters from Highschool DxD and Prototype have to team up to defeat this entity. This would require them to understand each other's powers and work together, leading to a lot of character development and exciting action scenes.
Well, it might involve the political intrigue. The complex politics in Game of Thrones could be combined with the NERV organization's secrecy in Evangelion. Maybe the different houses in Game of Thrones are vying for control over the Evangelion units. And the pilots of Evangelion could be seen as pawns in this political game, just like many characters in Game of Thrones are used by the powerful lords.
In this type of fanfiction, the Female Revan could be on a quest that spans both universes. For example, she could be searching for an ancient artifact that has significance in both the Star Wars galaxy and the wizarding world. Her journey would involve interacting with characters from both, like she might team up with Harry Potter to fight against a common enemy that is threatening both realms.
God could be the overarching power that created both universes. In the Naruto universe, it could be the origin of chakra, and in Star Wars, it could be the source of the Force. So, in fanfiction, a character might discover this connection and try to use it to their advantage, like a Jedi who travels to the Naruto world and discovers the chakra is a different manifestation of the Force from the same divine origin.