Another plot could be that his daughter has grown up without knowing much about her father. When they meet, she is initially skeptical of him. However, as she gets to know him, she realizes he's not the bad person the wizarding world made him out to be. They might go on adventures together, like exploring the Forbidden Forest in search of some magical creature that Sirius had heard about during his youth.
One possible plotline could be that Sirius Black has been away for a long time, perhaps in Azkaban or on the run. When he finally meets his daughter, there is an initial awkwardness. But as time passes, he starts to bond with her over shared magical abilities. For example, he might teach her how to transform into her Animagus form if she has the potential for it. They could also bond over stories of his time at Hogwarts with the Marauders.
A third plotline could be that Sirius meets his daughter in a time - traveling scenario. His daughter from the future somehow travels back in time and meets him when he was still a young man. This could lead to some really interesting interactions as he tries to understand his future self through his daughter. He might also try to change some things in his life based on the knowledge his daughter has of his future.
One possible plotline could be the daughter's discovery of her true identity. Maybe she was raised in an ordinary Muggle family and suddenly strange things start to happen. She begins to show magical abilities and then discovers she is Sirius Black's daughter. Another plot could involve her search for her father's legacy within the wizarding world, facing both friends and foes along the way.
A plotline might involve Sirius and Harry living together and Sirius trying to give Harry a normal family life. He could cook for Harry, help him with his homework, and they could have a pet together. Maybe they get a Kneazle, and Harry learns to take care of it with Sirius' guidance. This would be a contrast to the cold and often neglectful treatment he received from the Dursleys. And as Harry grows, Sirius could introduce him to his old friends like Remus Lupin in a more family - like setting, strengthening Harry's support system.
One possible plotline could be Sirius struggling with the disorder in secret while trying to maintain his tough exterior in the wizarding world. Maybe he's using it as a way to cope with the stress of his family situation and his time in Azkaban. His friends might start to notice small signs like his lack of appetite at meals or his weight loss, and gradually try to help him.
One possible plotline could be that Sirius and Remus initially struggle with their inappropriate feelings towards Harry. They might then realize it's wrong and instead focus on their roles as his protectors. They could channel their strong emotions into teaching Harry more about his parents and the wizarding world, turning a potentially dark concept into a positive mentoring relationship.
One possible plotline could be that Sirius Black has been under some dark magic influence. Maybe a powerful dark wizard has managed to manipulate his mind, making him believe Harry Potter is a threat to him or the wizarding world in some false way. This could lead to a series of events where Harry tries to prove his innocence and figure out what's wrong with Sirius. Another could be that there's a misunderstanding based on some prophecy or false information spread within the wizarding community. Sirius, being impulsive, jumps to conclusions and decides to disown Harry without fully understanding the situation.
Perhaps in the fanfiction, Sirius has been influenced by some dark magic or a curse that makes him feel hatred towards his daughter. It could also be that he discovers a secret about her origin that he finds unacceptable, like she was fathered by an enemy in some way. However, these are all very dark and complex reasons that go against his original character traits.
In this fanfiction, Sirius Black could take over the wizarding world by uniting the different houses at Hogwarts. He realizes that the division between the houses has caused a lot of problems in the wizarding community. So, he starts at Hogwarts, creating a new curriculum that encourages cooperation between the houses. This new unity gives him a strong base of support. He then uses this support to challenge the current leadership of the wizarding world. He might also discover some hidden secrets about the founders of Hogwarts that give him an edge in his takeover. For instance, he could find a powerful magic artifact left by one of the founders that helps him gain the trust of the wizarding population.
Another plotline could involve Draco's internal struggle. He is raised by Sirius, but still has the influence of his pure - blood Malfoy heritage. This could lead to a conflict within him. He might love and respect Sirius, but also feel the pull of his family's traditional values. This inner turmoil could drive the story as he tries to find his own identity, caught between two very different worlds.
The plot could involve the daughter growing up in the wizarding world, facing the challenges of her father's reputation. Maybe she's trying to clear his name while also learning magic at Hogwarts. She could discover some hidden secrets about her father's past and use that knowledge to make a difference in the wizarding community.
One possible plotline could be Snape using his position as master to make Sirius work on a dangerous mission for the greater good of the wizarding world, but Sirius is hesitant at first. Another could be Snape teaching Sirius some long - forgotten or dark magic that Sirius has to master under Snape's strict guidance.