In such a fanfiction, Harry Potter would probably grow up with a much different set of values. Doctor Strange is often about protecting the world from threats from other dimensions. So Harry could be trained to face threats that are not just from the dark wizards in his own world. He might also have access to some really cool artifacts from the Marvel universe. And his relationships with his friends would be different too. Instead of just Hogwarts classmates, he could have allies from different realms.
In this kind of fanfiction, the main antagonists could be a combination of the traditional Harry Potter villains like the Death Eaters and new threats from the Marvel side. For instance, Dormammu could somehow sense Harry's potential and try to either possess him or destroy him to prevent him from becoming a powerful force against him. And of course, there would always be some wizards in the Harry Potter world who are against any kind of change or outside influence, and they could also oppose Harry.
One idea could be a crossover where Doctor Strange uses his magic to visit the wizarding world of Harry Potter. He could meet Harry and help him with some of his more difficult magical problems, like dealing with a particularly powerful dark magic spell that the Hogwarts professors are stumped by.
Another possibility is a story in which a young wizard in the Harry Potter world discovers a hidden portal that leads to the dimension where Doctor Strange operates. This wizard, inspired by Strange, begins to study a new form of magic that combines the principles of both universes. They then return to Hogwarts and start to teach their friends this new hybrid magic, which causes quite a stir among the faculty and students alike.
If Harry Potter was raised by Dr. Strange in fanfiction, it could lead to some really interesting character developments. Harry might be more confident in handling strange and unknown magical situations, as Dr. Strange is constantly dealing with the unexpected. Also, he may have a different set of values. Instead of the house - based values at Hogwarts, he could be more focused on the balance of the multiverse like Dr. Strange.
One possible plot could be that the Doctor, with his time - traveling abilities, rescues Harry from the Dursleys at a young age. He then takes Harry on adventures across time and space, teaching him about different cultures and magic from various planets. Harry might learn unique forms of magic that are different from what he would have learned at Hogwarts, and he could use these new skills to fight against threats in both the wizarding world and the Doctor's universe.
Well, Naruto might learn some really cool magic stuff from Doctor Strange. He could use magic instead of chakra in some ways. Maybe he'd have a different fighting style, like using magic seals instead of hand signs for jutsu.
One possible plot could be that Doctor Strange uses his magic knowledge to train Harry in more advanced and esoteric forms of magic. Harry might learn to manipulate time and space in ways that are different from the normal Hogwarts curriculum. For example, he could learn to create stable time loops to study spells without the risk of negative consequences. This would give him an edge in his fight against Voldemort as he could plan better strategies and anticipate his enemy's moves.
One possible plot could be that Harry, as the son of Doctor Strange, discovers his magical abilities from both the wizarding world of Harry Potter and the mystic arts of Doctor Strange. He might use his combined powers to fight new and powerful dark forces that threaten both the magical and non - magical realms.
One common theme is magic exchange. For example, exploring how the magic from the Harry Potter universe would interact with the magic in Doctor Strange's world. Another theme could be character crossovers, like Harry meeting Doctor Strange and learning from him or vice versa.