Well, one possibility could be that the Dursleys suddenly realize Harry's importance and the power he holds. They might see how he could bring them some sort of status or protection in the wizarding world. So, they start to accept him, change their attitude towards him, and perhaps even help him in his magical studies in secret.
In this fanfiction, perhaps an outside force or event compels the Dursleys to accept Harry. Maybe there's a threat to the Muggle world that only Harry can help prevent, and the Dursleys, being self - interested as they are, figure out that having Harry on their side is the best option. This could lead to them treating Harry with respect and acceptance, and Harry might be a bit skeptical at first but gradually warms up to them.
In some interpretations, it could be that Harry finally snaps after years of abuse from the Dursleys. Maybe they pushed him too far one day and in a fit of rage, he uses his magic to end their lives. It's a very dark and extreme take on the Harry Potter universe.
Perhaps Harry uses his influence among his friends. Hermione could help him find some loophole in the Muggle - wizarding laws regarding property. Ron might provide some comical support, like trying to use some half - baked spell to make the Dursleys uncomfortable enough to leave. In the end, Harry evicts them and takes over the house, turning it into a place that's more welcoming for himself and his wizarding friends when they visit the Muggle world.
Perhaps in the 'harry gives birth at dursleys fanfiction', there's a new form of magic introduced. Harry could have been affected by a magical experiment that causes this strange phenomenon. The Dursleys, who have always mistreated Harry, now have to face the consequences of having such a unique and unheard - of event happening in their house. They might be in a state of panic and confusion as they try to figure out what to do.
Maybe Harry uses magic to make their house a mess. He could turn Dudley's room into a pigsty or make Aunt Petunia's precious china float and then smash. It's his way of getting back at all the years of mistreatment.
Perhaps Harry sues the Dursleys for false imprisonment. He realizes that all those years of being confined to his room or the cupboard were illegal. He enlists the help of Hermione, who is well - read in both wizarding and Muggle laws. They present a strong case against the Dursleys. As a result, the Dursleys face public humiliation in their neighborhood, and Harry finally gets the justice he deserves, while also starting to heal from the trauma of his childhood.
It could start with a build - up of small incidents. For example, the Dursleys constantly belittling him even after he has proven himself in the wizarding world. Then, one major event, like the Dursleys trying to sell his magic items or preventing him from going back to Hogwarts, causes Harry to snap. His killing of the Dursleys could then lead to a search for redemption or a fight against those who want to punish him unjustly, as he was pushed to his limits by their cruelty.
One possible plot could be that the Dursleys, out of their long - held hatred and envy, finally find a way to use dark magic against Harry. Maybe they make a deal with some dark wizards who provide them with a powerful curse. They manage to cast it on Harry when he's at his weakest moment, perhaps during one of his vacations at Privet Drive.
In this fanfiction, perhaps the Dursleys' constant abuse and neglect cause Harry to have some sort of mental or physical disability. It might show how he has to overcome not only the challenges of the wizarding world but also the trauma inflicted by his Muggle relatives. For instance, he could have problems with his legs from being locked in a cupboard for long periods, which would be a physical crippling, and then have to deal with the self - doubt and fear that comes with it.
Obviously, Harry Potter is one of the main characters. He is the one who is being accepted by the Dursleys. Then there are the Dursleys themselves - Vernon, Petunia, and Dudley. Vernon is the strict and often grumpy uncle, Petunia is the aunt who has always been envious of Lily (Harry's mother), and Dudley is the spoiled cousin. Their interactions with Harry will be central to the story as they shift from their previous negative attitude towards acceptance.
One possible plot could be that Voldemort realizes Harry's importance in a different way. Maybe he sees that Harry has some power or knowledge that could be useful to him in the long run. So, instead of wanting to kill Harry, he decides to rescue him from the Dursleys to gain his trust and manipulate him later. For example, Voldemort might think that Harry has a connection to some ancient magic that only he can access, and by saving him, he hopes to get access to it through Harry.