One common theme is family. Since it's about Harry having a little sister, it often explores the family dynamic. How they support each other, protect one another, and sometimes even have sibling rivalries. Another theme is identity. The little sister has to figure out who she is in the shadow of her famous brother.
Voldemort's remaining followers could be antagonists. They might target Harry's little sister thinking they can use her to get to Harry. They could try to kidnap her or use dark magic on her.
In a 'Harry Potter and His Little Sister' fanfiction, the sister could be a new student at Hogwarts when Harry is in his later years. She struggles to fit in because of being Harry Potter's sister. Harry has to help her deal with the pressure, make friends, and also face the threat of a new dark wizard who has a vendetta against the Potter family.
One great Harry Potter little sister fanfiction is 'The Potter Siblings' on FanFiction.net. It delves into the relationship between Harry and his fictional little sister in a really heartwarming way. The story shows how she grows up in the shadow of her famous brother yet manages to carve out her own identity within the wizarding world.
Well, obviously the little sister herself is a very important character. Depending on how she's written, she could be really kind - like a Hufflepuff at heart - or really brave and adventurous like a Gryffindor. Then there are the classic characters from the original series that often play a big role. Hermione would likely be there to offer her wisdom and help the little sister with her studies. Ron would be the comical friend, always getting into some sort of trouble but also being very loyal.
In some fanfictions, it could be through powerful magic spells that he discovers or is taught. Maybe he stumbles upon an ancient spell in the restricted section of the library that allows him to summon a family member. Another possibility is that he unknowingly activates some kind of magical artifact that has the power to bring a sister into his life.
One interesting 'Harry Potter little sister' fanfic could be where she has a unique magical ability that Harry doesn't have. For example, she might be able to communicate with magical creatures in a way no one else can. This could lead to all sorts of adventures, like helping Hagrid with some of his more dangerous beast - handling tasks.
Sister Lemon is a fictional character created specifically for this fanfiction. She doesn't exist in the original Harry Potter series. She's likely a character designed by the fanfiction writer to add a new element to the well - known wizarding world of Harry Potter.
One idea could be that Harry's little sister has a unique magical ability that no one else in the family has. For example, she might be able to communicate with magical creatures in a way that even Hagrid is impressed by. This could lead to all sorts of adventures where she helps solve problems in the wizarding world using this special skill.
One interesting fanfiction could be where Lucy discovers she has a unique magical ability that even Harry doesn't have. Maybe she can communicate with magical creatures on a deeper level. In this story, she uses her ability to solve a mystery in Hogwarts that has been baffling everyone. It could show her growing up in the shadow of her famous brother but still making her own mark in the wizarding world.