You can start by giving them unique personalities. For example, one could be really shy but have a hidden strength. Then, put them in different situations to show how they grow. Like when they face a monster, the shy one might find the courage to fight.
Another character that could be included is Clarisse. Her tough - as - nails attitude could contrast with the niece's, and they could start off as rivals but eventually become friends. Also, Tyson, Percy's cyclops half - brother. He could be like a big, protective figure for the niece, and his unique abilities could come in handy during adventures or when the niece is in danger.
One idea could be that Percy's niece discovers she has a unique power that no one else in the family has. Maybe she can communicate with sea creatures in a different way than Percy. Another could be that she gets involved in a quest that was thought to be only for the main heroes in the Percy Jackson world, and she has to prove herself to the other demigods.
A rogue magician who has a vendetta against Percy's family. He sees Percy's niece as an easy target to get back at Percy. He uses his magic to manipulate the world around her, causing confusion and danger. He might also be trying to steal her powers for himself to gain more influence in the world of magic and mythology.
Perhaps Percy's niece is suddenly transported to a different realm in the world of Greek mythology. This realm is in chaos due to some dark magic. She has to use her wits and any latent abilities she has to survive and find a way back. Meanwhile, Percy is on a quest of his own but starts to notice strange things that lead him to suspect his niece is in trouble. Eventually, their paths cross and they team up to save the day in this strange new realm.
One idea could be that the adopted children have special powers related to different elements, like one can control water in a unique way different from Percy. They could go on a quest to find a lost artifact that is key to their new family's safety.
Maybe it could be due to some powerful magic or a unique prophecy. In many fanfictions, unexpected events like this are often triggered by such elements.
There could be a fanfiction where the Jacksons 5 go on a fictional tour across the world and encounter different cultures. They learn new music styles and incorporate them into their own, which changes the direction of their music in this fictional story.
Yes, there are quite a few. You can find some on fanfiction.net. Just search for 'Percu Jacksons sister' and you'll get a list of stories. Some might focus on her adventures in the Percy Jackson world, while others could explore her relationships with the other characters.
Well, a frequent theme is her coming - of - age. In many fanfictions, she has to grow up quickly in the face of the threats in the world of gods and demigods. Also, the theme of friendship is common. She forms bonds with other characters, whether they are demigods or not. And sometimes, there's the theme of her uncovering secrets about her family or her own identity that have been hidden for a long time. This adds an element of mystery to the story.