Perhaps she's a sister who was thought to be dead but actually survived. She could have been corrupted by the experiences she had while being 'dead'. When she returns, she blames Percy for not saving her properly. This false blame leads her to betray Percy. She could start spreading rumors about Percy being a coward or a bad leader among the demigod community.
A common theme is the discovery of the sister's powers. For example, she might find out she can control water like Percy but in a different way. This adds an interesting twist to the story as they learn to use their powers together.
I really like 'A Sister's Tale in the Percy Jackson Universe'. In this fanfiction, the sister character brings a new dynamic to the story. It shows how she copes with the knowledge of the Greek gods and her relationship with Percy, which is full of both love and typical sibling spats. It's a very engaging read.
One great 'Percy Jackson and Sister' fanfiction is 'The Lost Sister'. It has an interesting plot where the sister has unique powers and they go on adventures together. The character development is really well - done.
Yes, there might be. Fanfiction is a vast world where all kinds of crossovers and creative ideas are explored. You can start by looking on popular fanfiction websites like Archive of Our Own or FanFiction.net. Just search for the specific concept and see if any authors have written about it.
Another theme is the sister's unique abilities. In a lot of fanfictions, the sister has some special power that sets her apart. This can range from control over a certain element to having a prophetic gift. It makes the story more exciting as they have to figure out how to use these abilities in different situations.
Well, one possibility could be that the sister discovers she has some unique powers that are different from Percy's. For example, she might be able to communicate with mythical creatures in a way that no one else can. This could lead to her getting involved in a quest to save a particular part of the mythical world that is in danger.
She might start off as a shy character. But as the fanfiction progresses and she discovers her connection to lemons, she becomes more confident. For example, if she uses lemons to make a magical item, she realizes her own capabilities and starts to stand up for herself more.
Percy would likely be very confused at first. He'd probably feel a mix of anger and sadness. He might start to question his own actions and wonder if he did something wrong to make his sister leave.
One possible plot could be Percy feeling a deep sense of betrayal and loneliness. He might struggle with his self - worth as he wonders why his sister left him. This could lead him on a journey to find answers about his family and his own identity, perhaps even uncovering secrets about his demigod heritage that his sister knew and he didn't.