If we swap Star and Marco, then the main antagonists could be those who were previously minor annoyances for the other character. For example, if Marco is now in Star's role, Ludo, who was a main antagonist for Star, could be an even bigger threat as Marco might not have Star's natural magical intuition to deal with him.
Well, perhaps in this swap AU, their powers are also swapped. Star has Marco's karate skills enhanced to a supernatural level, and Marco can now use Star's wand and spells. Also, the relationships they have with other characters could be reversed. Their friends might react very differently to this new 'them'.
Poseidon could play a regretful father. He may realize too late how much Percy has suffered and then try to make amends. For instance, he might secretly send gifts or powers to Percy to help him defend himself. Hades could be a secret mentor. He has a lot of knowledge about the dark side of the world and magic that could help Percy understand his situation better and find ways to fight back against his abusers.
Au999.9 was pure gold, and the gold content was no less than 999.9%. It was the highest value in the naming of jewelry. It was dark yellow in color and extremely pure. It shone with golden light and was bright. The markings were usually printed with words such as "Thousand Gold,""999 Gold," or "G999."
You could also swap the roles of the Black Organization members. For example, Gin could be the one who is secretly trying to undermine the organization from the inside, while someone like Vodka is in a more powerful position. This would completely change the dynamics of the whole 'Case Closed' underworld plot.
An AU fanfic is a type of fan fiction where the story takes place in an alternate universe with different settings or circumstances than the original work.
An au fanfic is a type of fan-written story that takes the characters or setting of an existing work and places them in an alternate universe or situation that differs from the original.
Polyjuice potion, which causes body swap in the wizarding world, can be a really interesting concept in fanfic. Writers can explore how characters experience life from another's perspective. For example, they might learn new things about themselves or other characters. It can lead to comical situations, like when characters are not used to their new body's abilities. It also allows for deep character development as they face challenges in a different form.
One idea could be that the vampires become the babysitters instead of the humans. They could struggle with the normal human tasks like making snacks or putting kids to bed in a very comical way.