One possible plot could be that Harry Potter, instead of growing up with the Dursleys, is found by the Winchesters. They would likely train him in hunting skills as well as magic. Harry might use his magic to aid the Winchesters in their battles against demons and other supernatural creatures. And he could also introduce them to the wizarding world, creating a whole new set of adventures and challenges as they try to co - exist in both worlds.
Perhaps the plot involves a magical artifact that has fallen into the wrong hands in the Supernatural world. Harry, with his knowledge of magic, and the Winchesters, with their experience in dealing with the supernatural, set out to retrieve it. They might face all sorts of challenges along the way, from vampires and werewolves to dark magic spells.
Well, perhaps the Winchesters, who are known for hunting supernatural beings in their own universe, find a way into the Harry Potter world. Maybe they sense some dark magic that the wizards in Harry Potter's world can't handle on their own. They then use their skills and knowledge of the supernatural to save Harry from a powerful dark wizard or a dangerous magical creature.
In a 'Harry Potter raised by Winchesters' fanfiction, it could be a wild ride. The Winchesters have a complex family dynamic and a lot of emotional baggage. Harry would be exposed to that as he grew up. He might develop a different personality compared to the canon Harry. Instead of the somewhat naive boy at the start of the series, he could be more street - smart and cynical. Also, the magic he uses could be combined with the Winchesters' hunting techniques, creating a whole new set of abilities for him to use against the dark forces.
Sam and Dean Winchester would interact with Harry like a big brother - type relationship. They would be protective of him, and teach him things. For example, Dean might show Harry how to use a gun while Sam could help him with research, both magical and non - magical. Harry would likely share his knowledge of magic with them, which would be fascinating for the Winchesters. He could also introduce them to his friends from Hogwarts like Hermione and Ron, and there would be some interesting cultural clashes between the hunter and wizarding cultures.
The plot could be that Harry, raised by demons, has unique powers that other wizards don't. For example, he might be able to communicate with dark creatures more easily. The demons could be using Harry as a tool to infiltrate the wizarding world. When he gets to Hogwarts, he starts to question his upbringing as he sees the kindness and different ways of magic there. He has to decide whether to stay true to his demon - raised self or embrace a new way of life.
One possible plot could be that Calypso, with her magical abilities, imparts a different kind of magic knowledge to Harry. Maybe she teaches him more nature - based magic, which is different from what he would learn at Hogwarts. Harry might grow up in a more isolated and peaceful environment with Calypso, away from the prying eyes of the wizarding world in Britain. This could lead to him having a different perspective on magic and his role in the fight against Voldemort.
The fanfiction might explore how Harry's relationship with the wizarding world is different. Growing up in Potter Manor, he could be seen as a more prominent figure from a young age. The manor itself could hold hidden chambers filled with challenges and rewards. Harry could stumble upon a chamber that tests his Potter lineage, like a series of magical trials. This would not only strengthen his magical abilities but also deepen his connection to his family name and the responsibilities that come with it.
One possibility could be that Harry Potter grows up with a strict military - like discipline on Kamino. He might be trained in unique combat skills that are different from what he learned at Hogwarts. He could also form unexpected alliances with the Kaminoans, and use their advanced cloning technology to his advantage in the wizarding world battles.
Perhaps the story could show Harry being isolated from the wizarding world he was meant to be a part of. Since demons are raising him, they might keep him away from Hogwarts and the positive influences there. He could develop powers that are a mix of wizardry and demonic abilities, which would make him a very different kind of character in the fanfiction universe. He might also have a different view on good and evil, as demons' moral compass is not the same as that of humans or wizards.
One possibility is that Harry would grow up to be a very different person. Dementors are creatures of despair, so he might be more withdrawn and less trusting. He could also have some very dark powers, having been exposed to the dementors' influence for so long.