The theme of redemption is also quite prevalent. Sirius has a complex past, and fanfictions often deal with him trying to make up for his mistakes or be redeemed in the eyes of others. And of course, the power of friendship is a big theme, as their relationship is rooted in that as well.
One common theme is mentorship turned into something more. Sirius often starts as a mentor - like figure to Harry, and then the relationship evolves. Another theme is the exploration of family - like bonds that transform into a deeper connection.
One common theme is the exploration of a different kind of friendship. Since Harry is female, the dynamic between her and Sirius is often re - imagined. Another theme is empowerment. The female Harry usually has to face challenges in a male - dominated wizarding world, and Sirius is there to support her growth.
One common theme is loyalty. Sirius Black is known for his loyalty in the original series, and in slash fanfiction, this loyalty often extends to his relationship with the other character. Another theme is the struggle against the prejudices of the wizarding world. Since slash relationships might not be as accepted in that world, they have to fight against that.
One common theme is loyalty. Sirius is extremely loyal to Harry, and this is often explored in fanfictions. Another theme is family. Since Sirius is like a father figure to Harry, stories often revolve around the idea of building a family. And the theme of redemption also appears, as Sirius has a complex past that he tries to make up for in relation to Harry.
One common theme is the idea of forbidden love. Since Sirius is an older figure in Harry's life, it's like a Romeo - Juliet type situation where society might not approve. Another theme is the power of connection and how their shared experiences at Hogwarts and in the fight against Voldemort can strengthen their bond romantically.
Love and Romance are very common. Since it's about Sirius Black and an OC, the development of their relationship, from the first meeting to falling in love, is often a central theme.
A theme that frequently shows up is the exploration of identity. With female Harry Potter being a different take on the original character, she is often on a journey of self - discovery, and Sirius plays a role in that. Also, the theme of family is important. Sirius can be seen as a sort of surrogate family member, and the fanfiction might explore how that relationship changes into a romantic one.
The theme of defying expectations also comes up a lot. The relationship between them goes against what is considered normal in the wizarding world. Fanfictions play with this idea, showing how they deal with the judgment and obstacles that come their way because of their relationship. It's about them finding their own way in a world that may not understand their bond at first.
Love against all odds is a very popular theme. Given Sirius's status as a wanted man at times and his family's dark reputation, a relationship with the reader is full of obstacles. Also, the theme of loyalty is often present. The reader and Sirius are loyal to each other in the face of all the chaos in the wizarding world. This loyalty is what binds them together in many stories.
One common theme is redemption. Sirius' father may have been a strict or even cruel figure in the original story, but in fanfiction, he could be seeking redemption for his past actions towards Sirius. Another theme is legacy. How does the Black family legacy affect the relationship between father and son? It could be a burden or a source of pride.