One plot twist could be that Regulus is not actually dead but was in hiding all this time. And his reason for adopting Harry could be related to some dark secret he's trying to protect. Maybe it has something to do with Voldemort and a way to defeat him that only Harry can be a part of.
I really liked 'Harry's New Family with Regulus'. In this fanfic, Harry's adoption by Regulus leads to a whole new dynamic in the wizarding world. It shows how they both grow together, with Harry getting to experience a more stable and loving family environment. There are also some cool sub - plots about how the other characters react to this new situation.
One great 'Harry Regulus' fanfic is 'The Lost Prince'. It delves deep into the relationship between Harry and Regulus. The story shows how Harry discovers Regulus's past and how it impacts his own journey. The character development is well - done, and the plot keeps you hooked from start to finish.
The fact that he was part of the Black family, a family with such a complex and dark history in the wizarding world, adds to the allure. Fanfic can expand on his experiences within the family, his upbringing, and how it shaped him into the person he became. It can also show how his actions, like his discovery of Voldemort's Horcruxes, could have had a greater impact on the overall story of Harry Potter.
At first, it might be a bit of a rocky start. Harry, having grown up without a proper family, could be wary of Regulus. But as time passes, he starts to see Regulus as a father figure. Regulus, on the other hand, is determined to make up for his past mistakes by raising Harry right. So he showers Harry with care and magical knowledge, and they gradually form a strong bond.
One common theme is family. Since Harry is being adopted, the new family dynamic is explored. Whether it's a loving family like the Weasleys or a more complex situation like with Snape, the idea of family and what it means to Harry is central. Another theme is self - discovery. Harry often has to re - evaluate who he is in the context of his new family. For example, if he's adopted by the Malfoys, he has to figure out how to fit into a family with different values than what he's used to.
Yes, there are likely some fanfictions out there with that concept. You can try searching on major fanfiction platforms like Archive of Our Own or Fanfiction.net.
There's 'Regulus Black: Redemption'. This fanfic focuses on Regulus' journey towards redemption after his actions in the original story. It gives a lot of insights into his character and his relationships with other characters in the Harry Potter universe, like Sirius and Kreacher. It also has some really interesting plot twists that keep you hooked.
Harry could be a young, orphaned boy with a lot of potential. He might be a bit naive at first but has a kind heart. Reno could be an older, more experienced person, maybe a warrior or a survivalist. He has seen a lot in his life and has a tough exterior but a soft spot inside.
Harry could develop a more guarded personality. Since the Malfoys have a certain reputation, he may need to be careful about his actions and words. He might also become more calculating in his interactions, learning from the Malfoy family's political maneuvers.