Well, it might start with the Dursleys doing something truly heinous, like trying to permanently get rid of Harry's magic. Harry, feeling cornered and betrayed, decides that enough is enough. He realizes that as long as they are alive, he will never be truly safe or free, so he takes drastic action. However, this goes against the core values of the original series, which is why it's such a controversial fanfiction idea.
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.
The 'harry kills the dursleys fanfiction' could be a way for the author to explore the darker side of Harry's character. Perhaps there is a build - up of all the pain and anger he has stored inside from his time at the Dursleys' house. It could also be a way to show how power can corrupt, even someone as good - natured as Harry. For example, if he is constantly provoked by the Dursleys and has no one to turn to for support, he might make a rash decision that he will later regret. But it also makes us think about the limits of human endurance and how far a person can be pushed before they break.
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.
I haven't actually come across a 'Dursleys kills Harry Potter' fanfiction. It's a rather disturbing concept considering how the story of Harry Potter is centered around his survival against Voldemort. The Dursleys are just part of his Muggle upbringing with their own brand of meanness. If there were such a fanfiction, it would probably change the whole trajectory of the story. For example, the wizarding world would lose its Boy Who Lived, and it would be interesting to see how the characters like Dumbledore or Hermione would react to such a tragic event.
There are likely 'Harry Potter Kills Dursleys' fanfictions. Fanfic writers often like to explore extreme scenarios. In this case, it could be a way to show how far Harry could be pushed. It might also be a commentary on the Dursleys' horrible treatment of Harry. But this goes against the somewhat forgiving nature of Harry in the original books.
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.
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.
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.