In these fanfictions, a recurring theme is the change in their relationship. The pregnancy can bring them closer together or create new tensions. Also, the theme of protecting the unborn child from potential threats in the wizarding world, whether it's dark wizards or the prejudiced views of others, is quite common. Additionally, there may be exploration of how Hermione's academic life is affected and how Sirius adapts to the idea of becoming a father, which are all interesting aspects that authors like to explore.
A big theme is the exploration of Hermione's character growth. With Sirius as her guardian, she might be exposed to different aspects of magic and life that she wouldn't have otherwise. For example, she could learn more about the darker side of magic and how to combat it. Also, the theme of loyalty often comes up, as Sirius is loyal to Hermione and she to him in return.
Protection is also a big theme. Given Sirius' nature, he feels a sense of responsibility to keep Hermione safe. This could be from dark wizards or from the general dangers that lurk in the wizarding world. Sometimes, it's about protecting her reputation or her place at Hogwarts too.
One common theme is redemption. Sirius has had a troubled past, and Hermione could be seen as the one to help him fully redeem himself. Another theme is the power of love across different generations. Since they are from different age groups in the original series, the fanfictions might explore how love can bridge that gap.
Some fanfictions might explore the magical world's reaction to such an unusual pairing. For example, how would the other characters like Harry or Ron react? Or what about the wizarding society's views on this relationship? This adds an extra layer of complexity and drama to the story, making it more interesting to read.
There are quite a few out there. Some might be found on popular fanfiction websites like Archive of Our Own. You can search for specific tags related to Sirius and Hermione and pregnancy to narrow down the results.
Often, there could be themes related to acceptance. Lucius may need to accept Hermione in a new light, and she may have to come to terms with the Veela side of things during the pregnancy. Also, there might be a theme of facing the judgment of the wizarding world. Their relationship is not a typical one, and with a pregnancy involved, they would likely face a lot of scrutiny from others.
One common theme is mentorship. Sirius can be seen as a mentor to Hermione, guiding her with his more worldly wizarding knowledge. Another theme is the idea of family. Since Sirius is an outsider in his own family, and Hermione has Muggle - born status, they form a kind of surrogate family for each other.
One common theme is the exploration of an unconventional friendship. Sirius and Hermione come from different generations in the wizarding world, so their friendship defies the norms.
A lot of these fanfictions explore the idea of forbidden love. Hermione and Sirius come from different generations in the original series, so when he's portrayed as dark, it adds an extra layer of taboo to their relationship. Also, mystery and adventure are common. They might be on a quest together, with Sirius' dark side influencing the journey in various ways.
One common theme could be the exploration of forbidden love. Since Sirius is much older and in a different generation than Hermione in the original series, the idea of their relationship goes against the norms. Another theme might be the struggle with one's emotions. Hermione, being a rational character, lusting for Sirius could lead to her internal conflict between her logical side and her new - found emotions.