The two universes can be blended well by focusing on the values of the characters. Both Naruto and the characters in Case Closed have a strong sense of justice. You can build a story around this common value. Maybe there is a conspiracy that threatens the justice system in both worlds. The ninjas and the detectives would then come together to uphold justice. This could involve Naruto using his rasengan to break through physical barriers during investigations, while Conan uses his sharp mind to figure out the motives behind the conspiracy, which are often related to power struggles or revenge, just like in his own world.
The RWBY and Naruto universes can be blended well in fanfiction by having the characters share their skills. For instance, Yang's strength could be combined with Naruto's Rasengan for a super - powerful attack. Also, the different settings can be merged, like having the Hidden Leaf Village exist in the same world as Vale.
To blend the two universes well, you could start by establishing some common ground. For example, both have elements of mystery and danger. You could have the magic from the Harry Potter universe interact with Slenderman's spooky abilities. Maybe Slenderman's presence distorts the magic around him in Hogwarts, causing strange things to happen. Another way is to introduce a crossover object or character that belongs to both worlds in a way.
Another way is to have a character from one universe end up in the other, like Venom ending up in the Young Justice world. Then, through that character's eyes, we can explore the new universe and see how it clashes or meshes with their own. You could also introduce some sort of magic or technology that bridges the two universes, like a portal - creating device that was created by a mad scientist in both universes independently, but when activated, it links the two. This would bring in elements of mystery and discovery as the characters figure out how to use it and what it means for their respective worlds.
The first step is to find common elements. For instance, both universes have strong - willed characters. You can start by having a character from one universe admire the qualities of a character from the other. Then, introduce a common threat that requires the combined efforts of both Naruto and Sekirei characters. Also, you can blend the power systems. Maybe a Sekirei could learn to use chakra or Naruto could gain a Sekirei - like power.
The power systems can be blended. In Naruto, there are chakra and jutsu, while in Pokemon there are different types of moves and abilities. A story could have a Pokemon girl teach a Naruto character about the unique aspects of Pokemon powers, and in turn, the Naruto character could share some ninja techniques. Maybe a Pokemon could learn to use a basic ninja move like the substitution jutsu, and a Naruto character could learn to communicate with Pokemon like the Pokemon girl does. This exchange of skills can help blend the two universes.
The cultures of their universes can be blended. Naruto's world has a strong sense of community and loyalty within the ninja villages. Sephiroth's world might have different values. By having the characters interact and learn from each other's cultures, like Naruto teaching Sephiroth about friendship and she teaching him about some unique aspects of her world's technology or magic, it can blend the universes well. Also, the settings can be merged. Maybe there's a place that exists in both universes but in different forms, and they have to go there together.
In Naruto in Overwatch fanfiction, the concept of elemental jutsu can be really interesting. Naruto's fire - style jutsu could be related to some of the fire - using heroes in Overwatch like Ashe. His water - style jutsu could be used in a creative way, like for defense or to put out fires in the Overwatch maps. And the idea of chakra could be something new to the Overwatch universe. It could be a power source that some characters start to tap into, leading to new abilities and power - ups.
Well, you can start by having the settings interact. For instance, the forest in 'Into the Woods' could connect to the forested areas around Forks in 'Twilight'. The characters' traits can also be combined. The vampires' elegance and strength in 'Twilight' could be paired with the cunning of some 'Into the Woods' characters like the fox. Also, the magical elements from 'Into the Woods' like spells and wishes could influence the events in the 'Twilight' universe.
You can blend the two universes by focusing on their common themes. For example, both Sonic and Hello Kitty are about friendship. So, a story could be built around the concept of making new friends across different worlds. Have Sonic meet Hello Kitty's friends like My Melody and they all learn from each other's positive qualities.
The key is to find common elements. For example, both universes have different forms of power. In Naruto, there are chakra - based powers, and in Mass Effect, there are biotic and tech powers. The mind - control aspect could be related to a new form of chakra or a corrupted biotic power. Characters from both universes could be brought together through a mysterious portal or some sort of interdimensional rift.