One possible storyline could be that Harry's experience with cancer makes him more resilient. He might have faced his own mortality at a young age, so when he enters the wizarding world, he has a different perspective on danger. For example, he may not be as afraid of Voldemort as others because he has already fought a life - threatening battle with cancer.
It could be that Harry's cancer diagnosis was kept a secret from the wizarding world. When he arrives at Hogwarts, he has to hide his condition while also dealing with the challenges of school. This could create a lot of internal conflict for him, as he has to balance his studies, making friends, and dealing with his health issues all at once.
In this fanfiction, it could be that Hogwarts has been shut down due to some great danger. Harry Potter then decides to gather a group of like - minded young wizards and witches. They form their own makeshift magical school in a hidden location. They have to learn magic without the guidance of Hogwarts' professors, so they rely on old magic books and their own wits to develop their magical abilities and face the threats that led to Hogwarts' closure.
His relationship with the Dursleys might be more complex. They could be even more cruel, seeing him as a burden because of his cancer. Or, in a different take, they might feel a bit of pity and be slightly less horrible. As for his friends at Hogwarts, he might be more guarded at first. He has been through a tough time with his health, so it could take him longer to open up to Ron and Hermione.
One possible storyline could be that Voldemort manages to attack the Dursleys' house before Hagrid can arrive to take Harry to Hogwarts. Maybe a Death Eater discovers Harry's location early on and Voldemort decides to end the threat immediately. Another could be that some dark magic from Harry's parents' past catches up to him as a baby, and he succumbs to it, never making it to Hogwarts. It could also be that a wizarding accident occurs in the Muggle world that involves Harry and results in his death, like a misfired spell from a rogue wizard in hiding.
One possible reason could be that he was under the influence of a powerful dark magic or a curse that made him lose control. Another reason might be that he was tricked into believing Hogwarts was a threat to the wizarding world in some extreme way. Maybe a powerful enemy manipulated him to think that destroying Hogwarts was the only way to save everyone.
One possibility could be that they meet in a muggle setting, like a local park. Maybe Hermione is reading a book on a bench and Harry, who is always curious, approaches her to ask what she's reading. Another could be that they both end up at the same orphanage for a short time and form a bond over their shared sense of being different from the other kids.
In such a fanfiction, Harry could die from an accident. For example, if he discovers magic early and while experimenting without proper guidance, something goes horribly wrong. Maybe he stumbles upon a dangerous magical artifact near his home that has a curse and it kills him before he ever gets to Hogwarts. It would be a very different story from the original, as his death would change the whole dynamic of the wizarding world that we know from the books.
Hermione Granger could also be a possible Hogwarts heir. She is extremely intelligent and has a thirst for knowledge about Hogwarts' history and magic. Her Muggle - born status might seem to be a contradiction, but it could also be part of what makes her unique as the heir. She could bring new perspectives and use her vast knowledge to unlock secrets about the heir's role and the future of Hogwarts.
One reason could be to create a unique and unexpected story. By introducing a non - magical, real - world illness like lung cancer into the magical world of Harry Potter, the author can explore how the characters would react. Another reason might be to show the contrast between the muggle world, where such diseases are common, and the wizarding world, which has magic to deal with most problems. Maybe the author has some personal experience related to lung cancer and wants to incorporate it into a story they love.
It could be that there's a powerful enemy that has taken over Hogwarts and Harry, in a desperate attempt to stop this evil from spreading, resorts to destroying the school. He might think that rebuilding it later is better than allowing it to be used for evil purposes. For example, if Voldemort had found a way to permanently taint the magic of Hogwarts, Harry might see destruction as the only option.
One possible plot could be that Harry leaves Hogwarts to hunt down the remaining Death Eaters on his own. He might feel that he can't put his friends in danger anymore and takes it upon himself to rid the wizarding world of the last remnants of Voldemort's followers.