There probably is. The Harry Potter fandom is huge and full of diverse ideas. Writers might explore this idea to add new twists to the story, like how Harry's relationship with Sirius would be re - imagined if he were his daughter, and how it would change the overall plot dynamics.
One interesting fanfiction could be about Sirius Black's daughter joining Harry Potter and his friends on their adventures at Hogwarts. She might inherit her father's brave and rebellious spirit, causing some interesting twists in the story.
One possible fanfiction could be about Sirius Black's daughter discovering her father's true nature and his relationship with Harry Potter. She might start at Hogwarts and face some challenges due to her father's reputation. For example, some students might be wary of her at first, but she gradually proves herself to be a brave and kind witch, just like her father.
Fanfiction about these three can take many forms. For example, there could be time - travel fics where Harry goes back in time and meets Regulus and Sirius when they were younger. This could lead to all sorts of interesting plot twists, like Harry trying to prevent Regulus from joining the Death Eaters in the first place. Or it could be a fic where Sirius survives and he and Harry explore the secrets of the Black family together, including things that Regulus left behind. There are also fics that focus on the emotional bonds between the characters, showing how the different personalities of Regulus, Sirius, and Harry interact and influence each other.
She could also be an innovator. She might come up with new spells or magical techniques. Since she has the blood of Sirius Black in her, she could be a natural at magic and use her creativity to solve problems that Harry and his friends face, like finding a new way to combat the Dementors or a more effective way to pass their exams without the use of cheating spells.
One possible plot could be that Harry discovers the truth about her real parentage early on. She then has to deal with the implications of being Sirius' daughter while still at Hogwarts, facing both the admiration and suspicion from others.
One great fanfiction in this theme could be 'The Black Heir and the Boy Who Lived'. It delves into the relationship between Sirius Black's daughter and Harry Potter as they face the challenges of the wizarding world together. They start off as friends but gradually develop deeper feelings as they uncover secrets about their families and fight against the dark forces.
Yes, there are some fanfictions with such an interesting concept. In these fanfictions, the authors usually re - imagine the story world of Harry Potter. They might change the relationships and character backstories to fit this new idea of Harry being Sirius's daughter. It often leads to a completely different take on the original story, with new plotlines emerging from this changed family dynamic.
One possible reason could be a misunderstanding. Maybe some false information was spread about Harry that made Sirius believe he had done something unforgivable. For example, if there were rumors that Harry was involved with dark magic in some way, Sirius, who has a strong aversion to the dark side, might be quick to disown him.
One great 'Harry Potter Sirius Black fanfiction' is 'Padfoot Returns'. It really delves into Sirius's character and his relationships within the wizarding world. The story has a great plot that keeps you hooked from start to finish.