One possible motive could be that the Potters discovered some dark plot by the Malfoys involving Harry. Maybe they found out that the Malfoys were planning to indoctrinate Harry into their pure - blood supremacist ideology against his will. So, to protect Harry from that, they kidnapped him.
Well, obviously, the relationship between the Potters and the Malfoys becomes extremely hostile. The Malfoys would see the Potters as thieves who stole Harry from them. For Harry, his view of the Potters might be initially one of confusion. He was with the Malfoys, and now he's with the Potters. But over time, he might come to see them as his true family.
Sirius Black could also be part of it. He was Harry's godfather. He might have escaped from Azkaban earlier in this fanfic. He teams up with the Potters to rescue Harry. He could be the one who scouts out the Dursleys' house before the actual rescue operation, using his skills as an Animagus to stay hidden.
Well, one way could be that Draco has some sort of ulterior motive. Maybe he wants to use Harry to bargain with the Order of the Phoenix or the Death Eaters. He might think that having Harry in his custody gives him power. Another possibility is that Draco is actually trying to protect Harry from something he knows is coming, but his methods are extreme. For example, he could have heard of a new dark wizard threat and believes that by kidnapping Harry, he can keep him safe in a secret location.
Perhaps there's a plot against Harry by some dark forces, and the Potters believe that only they can protect him properly. They might think that the people who have been taking care of Harry so far are not equipped to handle the new and more dangerous threats. Also, it could be that the afterlife in the wizarding world has some rules or opportunities that allow them to try and get Harry back into their family fold. They could have been given a second chance, so to speak, and are eager to take it.
Yes, they might. Just like any other group of people, those who identify as Blacks or are part of the Potter family name (if we assume there are real people with that name) could be fans of the Harry Potter series and thus read fanfiction. Fanfiction offers a wide range of interpretations and extensions of the original story, and anyone with an interest in the magical world of Harry Potter could be drawn to it.
Well, in the 'Harry Potter raised by Potters' fanfiction, it really strays from the original in terms of family influence. In the books, the Dursleys' non - magical and often cruel treatment of Harry was a big part of his story. But here, with the Potters, he has a loving and magical family. This means his values and worldviews are likely to be different. For instance, he might be more open - minded about different magical traditions from the start. Also, the role of Hogwarts in his life might change. Instead of being a sort of refuge from the Dursleys, it could be more of an extension of his family's magical world. And his relationship with the Hogwarts staff, like Snape, could be very different. Since he has been raised in a positive family environment, he might be more able to handle Snape's initial hostility in a different way compared to the original Harry.
It could also be that the Potters are under some sort of magical influence or curse. In the fan fiction world, there could be a dark force at play that makes them see the twins as more important. This force might be manipulating their emotions and perception, leading to the neglect of Harry.
A common plot in Draco Malfoy kidnapped fanfiction is that Draco kidnaps a fellow student to get information. He suspects that this student has knowledge about a hidden magical artifact or a secret spell that could help him gain power or status. Maybe he's fallen from grace in the Slytherin house or among the Death Eaters, and he thinks this piece of information will redeem him. Or perhaps he kidnaps someone who he believes has seen something they shouldn't have, like a Slytherin plot against the school, and he wants to keep them quiet.
One interesting plot could be the development of an unexpected friendship between the kidnapped character and Draco. Maybe they start to understand each other's motives and past traumas, leading to a change in their relationship from captor - captive to something more complex.