One plot idea is that Harry, as Sirius's son, would have a different relationship with the Marauders' Map. Since it was created by his father and his friends, he might unlock new abilities or secrets within it. He could use it to uncover hidden passages in Hogwarts that lead to places related to the Black family's history. This could also put him in the middle of a conflict between different factions in the school who either want to use the map's secrets for good or bad purposes.
A plot could involve Harry having a closer connection to the wizarding underworld due to Sirius's past associations. This might lead him to discover secrets about the Dark Arts that are hidden from most of the wizarding world. He could also face more opposition from the Ministry of Magic as they are always suspicious of Sirius. Maybe he has to fight against false accusations of being involved in dark magic activities, just like Sirius had to deal with in the past.
One interesting plot idea could be Harry growing up with Sirius's wild and rebellious spirit. He might be more daring in his adventures at Hogwarts, perhaps even forming a secret group earlier to oppose the Dark Arts in a more proactive way. Another could be the exploration of how Sirius's family history and his status as a Black influence Harry's view of pure - blood ideology. He could struggle with the expectations that come with being a Black heir while also trying to uphold the values he learned from his friends and Dumbledore.
One plot idea could be that fem Harry Potter discovers a hidden prophecy that involves Sirius Black and they have to work together to figure out what it means. Along the way, they face challenges from dark wizards who also want to get their hands on the prophecy.
In a 'Harry Potter meets Sirius Black fanfiction', it could be interesting if Sirius and Harry found a way to time - travel. They could go back to the time when James and Lily were alive. This would not only allow Harry to meet his parents but also give Sirius a chance to change some events that led to his downfall. They might also interfere with the actions of Voldemort in the past, creating a whole new timeline and a different future for the wizarding world.
One idea is that a dark wizard targets Remus Lupin and Sirius Black because of their close relationship with Harry Potter. The fanfiction could focus on how they protect themselves and Harry, and how this situation brings out new aspects of their magical abilities and their bond with each other. They might have to seek help from some unexpected allies within the wizarding world to survive.
A possible plot is that Sirius Black gets a tip - maybe from an unexpected source like a house - elf - that Harry Potter is being lured into a trap. Sirius races against time to reach Harry. When he does, Harry is in a wizarding duel with some powerful dark wizards. Sirius jumps into the fray, using his own powerful magic skills. He manages to deflect the dark spells aimed at Harry and then they both apparate away to safety. This could lead to a deeper bond between them and also new revelations about Sirius' past that help Harry in his fight against Voldemort.
In some fanfiction, yes. Fanfiction writers often like to play with the relationships in the Harry Potter universe. They might create a scenario where Sirius Black is Harry Potter's father, perhaps exploring how this would change the story's dynamics, the relationships between characters, and the overall plot.
Well, a plot could involve Harry having to deal with the memories and legacies of both his fathers. He might discover hidden secrets about James and Sirius that were kept from him. Maybe he uncovers a powerful magic that they were working on together before they died. Also, the relationship between Harry and his friends could change. Hermione might be more intrigued by the new historical and magical implications of his parentage, while Ron could be a bit jealous at first but then come to embrace it as part of Harry's identity.
One idea could be that Harry discovers his true parentage and has to struggle with his identity. He might be torn between the side of good that he has known all his life and the dark legacy of Bellatrix. Another plot could involve him facing discrimination from both the wizarding world that hates Bellatrix and the Death Eaters who might see him as a tool or a threat. For example, he could try to use his knowledge of Bellatrix's magic, which might be more complex and dark - tinged, to fight against Voldemort in a different way than in the original story.
Perhaps Sirius Black's daughter has a special connection to Harry through a long - forgotten prophecy. They start to notice strange coincidences and shared dreams. As they investigate, they find out that their destinies are intertwined in a way that could change the wizarding world. It could involve a journey to find a lost magical artifact that holds the key to fulfilling the prophecy.
There are definitely some 'Harry Potter is the son of Sirius Black' fanfictions. You can find them on various fanfiction platforms. A lot of these fics play around with the idea of how Sirius would have raised Harry if he had been his biological father. It could lead to a much more rebellious Harry perhaps, as Sirius has that streak in him. Some also delve into how this would change the prophecy and the whole battle against Voldemort.
One idea could be Sirius teaching Harry all the secret passages around Hogwarts that he knew as a student. Another could be Sirius introducing Harry to the wizarding world's underground music scene. Or perhaps Sirius helping Harry deal with his nightmares about Voldemort by sharing his own experiences of facing dark magic.