In a fanfiction crossover, the personalities of the characters would make for some interesting interactions. Star is very headstrong and adventurous, while the characters in 'Welcome Home' seem to be more community - based and homey. So, Star could come in and stir things up. She might introduce new ideas and ways of doing things to the 'Welcome Home' gang. For instance, she could teach them about different dimensions, which could open up a whole new world of possibilities for them in their own little world.
A crossover might involve the art styles of the two. 'Welcome Home' has a very unique, somewhat nostalgic art style. If the characters from 'Star vs the Forces of Evil' were drawn in that style, it would be really cool. They could have an adventure where they have to adapt to the new art - like the world is made of paper or something. And they'd have to be careful not to rip it while fighting enemies. It would be a fun and creative take on a crossover.
One interesting crossover could be the characters from Naruto learning about the magic in Star vs the Forces of Evil. For example, Naruto might be intrigued by Star's magic wand and try to understand how it works compared to his own chakra-based techniques.
First, you need to know both universes well. Read up on the characters, their backstories, and the rules of their respective worlds in 'Star vs the Forces of Evil' and 'Welcome Home'. This knowledge will help you create a believable crossover. For example, if you want to bring Marco from 'Star vs the Forces of Evil' into 'Welcome Home', you should know how he'll react to the new environment based on his character traits.
In this fanfiction, perhaps there could be a plot where some of the Pokemon are accidentally transported to the dimension of Star vs the Forces of Evil. Star and Marco then have to figure out how to get them back home while also dealing with the chaos that the Pokemon cause in their world, like Pikachu's electric shocks causing power outages in Mewni.
Another aspect could be the cultural exchange. Naruto's world has its own unique traditions and values, and Star's world is also full of strange and wonderful cultures. In the fanfiction, they could learn from each other's cultures. For instance, Star could introduce new forms of art and music to Naruto's village, while Naruto could teach her about the importance of loyalty and hard work within his ninja clan.
There could be a fanfiction that puts Evil Star in a situation where she has to face her own good side. Maybe she gets hit by a spell that makes her see the consequences of her evil actions. This could lead to an internal struggle within her, and the story could explore whether she would change or double down on her evil ways. It would be really interesting to see how the writer develops her character in such a scenario.
One interesting idea could be exploring a darker side of Marco's character. Maybe he has some hidden powers or motives that are revealed in the fanfiction. Another idea could be his relationships with other characters in this 'evil' scenario. For example, how does his friendship with Star change when he takes on this new, darker persona.
One interesting fanfiction could be about an alternate universe where Star and Marco's roles are reversed. Another might focus on a backstory for one of the minor characters like Pony Head. And there could also be fanfictions that explore what would happen if the magic in the 'Star vs. the Forces of Evil' world suddenly disappeared.
There might be a fanfiction that focuses on the backstory of the villains in 'Star vs Forces of Evil'. It could explore their motives and how they became the forces of evil in the first place. For example, it could show how Toffee's past experiences shaped his hatred for the Butterfly family.
One interesting fanfiction could be about Star and Marco exploring a new dimension that was previously unknown in the show. In this dimension, they encounter strange creatures and have to use their combined skills to find a way back home.
One interesting concept could be characters from different universes within the fanfiction meeting and interacting. For example, Star from 'Star vs the Forces of Evil' might meet characters from other popular shows. This can lead to unique storylines and character developments. Another concept could be the combination of different magical elements from the show and the crossovers. It can create new powers and challenges for the characters.