In some 'Harry Potter sister womb fanfiction', the sister's very existence in the womb could be a prophecy fulfillment. Her birth might be surrounded by strange magical events. For instance, when she was in the womb, all the plants in the vicinity of her mother started to glow, and as she grows, she discovers that she has a special bond with nature magic that was first signaled during her time in the womb.
There could be a lack of widespread 'Harry Potter womb lemon' fanfictions as it's not a common or recognized trope within the mainstream Harry Potter fan community. But generally, in Harry Potter fanfiction, some focus on the romantic relationships of the characters. For instance, Hermione and Draco pairings which deviate from the original pairings in the books and movies.
I'm not entirely sure specifically what 'harry potter womb fanfiction' is about as it's not a common or official part of the Harry Potter franchise. It might be some very niche, non - canonical fan - created stories that could involve strange or unorthodox concepts related to the idea of a 'womb' within the Harry Potter universe. However, it could also potentially be something misnamed or not really related to what it seems at first glance.
Then there's their parents. In the fanfiction, the mother could be a key figure as the one carrying the sister in the womb. Her experiences during pregnancy might be detailed, like any strange feelings or dreams she had. And the father, who might be involved in protecting the family during this time when the sister is in the womb. Their family bond is often an important aspect in these stories.
One interesting 'Harry Potter x Twin Sister' fanfiction could be about their adventures together at Hogwarts that are not fully explored in the original books. For example, they might discover a hidden chamber in the castle and have to work together to solve the mystery within it.
One interesting plot could be the twin sister having a special magical ability that Harry doesn't. For example, she might be able to communicate with magical creatures in a way no one else can. This could lead to her helping Harry in his adventures in a unique way, like getting help from a phoenix or a centaur when they are in a tough situation.
One possible plot could be that the older sister is a powerful witch who has been secretly protecting Harry all along. Maybe she has her own network of allies within the wizarding world that she uses to keep an eye on him. For example, she could be in contact with some of the more reclusive magical creatures who provide her with information about Voldemort's movements.
Well, one interesting idea could be the unique relationships that form within the harem. For example, how the sister character might interact differently with each member of the harem, bringing out new sides of their personalities. It could also explore the magical world from a new perspective as the sister's experiences are often different from Harry's. Another aspect could be the power dynamics within the harem, who holds more influence over the sister and how that affects the group as a whole.
In some fanfictions, Harry's sister might be sorted into a different house than him, like Slytherin. This would create a lot of internal conflict within the family as well as at Hogwarts. It could lead to a situation where Harry has to defend his sister against the prejudices of his friends. Or perhaps she has a prophecy related to her that ties into Harry's own destiny, and they have to figure out how to fulfill both prophecies without sacrificing one another.
One interesting plotline could be the twin sister having a unique magical ability that Harry doesn't. For example, she might be able to communicate with magical creatures in a way no one else can. This could lead to her getting involved in adventures that are separate from Harry's at Hogwarts, but still end up being connected in some way, like when she discovers a secret about a creature that is related to a dark wizard who is also after Harry.
One interesting 'Harry Potter twins sister fanfic' could be where the sister has a unique magical ability that even the twins are amazed by. 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 as she helps the twins and their friends at Hogwarts.