Well, perhaps the plot could involve Stephen Strange using his magic knowledge to train Harry in different forms of magic that are more advanced than what he learned at Hogwarts. Maybe he teaches Harry about dimensional magic, which could be used to access new places or even different timelines in the wizarding world.
Perhaps in the fanfiction, Harry Potter gets lost in the multiverse and ends up in the world where Stephen Strange operates. Strange takes Harry under his wing, teaching him about the different forms of magic beyond what he knows from Hogwarts. Harry, in turn, could introduce Strange to some of the more unique magical creatures from his world, like the Hippogriff.
The magic could blend in interesting ways. Harry's wand - based magic might be enhanced by Dr Strange's more esoteric and hand - gesture - based magic. For example, Harry could use his wand to direct the energy patterns he learns from Dr Strange.
Their magical styles could clash because Harry's magic from the wizarding world is more traditional and based on incantations and wand - work. Stephen Strange's magic, on the other hand, is more about hand - gestures and drawing energy from different dimensions. However, they could also complement each other. Harry could learn from Strange how to access more raw and powerful forms of magic, while Strange could learn about the subtleties of wizarding magic from Harry.
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.
Well, it could be that Dr Strange uses his magic knowledge to train Harry Potter in different ways of spellcasting. Maybe he shows Harry how to manipulate time and space while casting spells, which could give Harry an edge in fighting Voldemort. He might also teach Harry about different magical dimensions and how to draw power from them.
One possible plotline could be that Harry Potter discovers a portal to the Marvel universe and meets Stephen Strange. Strange then takes Harry under his wing to teach him the mystic arts, which Harry uses to enhance his own magic when he returns to Hogwarts. Another could be that a threat in the wizarding world is so powerful that the Ministry of Magic seeks help from Stephen Strange, and he comes to Hogwarts to help fight the dark forces using his unique abilities.
Harry Potter's character would develop a sense of mystery. Doctor Strange's magic is often associated with the unknown and the arcane. After being trained by him, Harry might start to act more mysteriously, keeping his new skills and knowledge under wraps until the right moment. This new air of mystery would not only add to his allure but also make him a more unpredictable opponent for Voldemort. His relationships with his friends might also change. They might see him as someone who has moved to a different level of magic, and there could be some initial distance or envy, but Harry would also be able to use his new skills to protect them better in the long run.
The magic systems could also interact in a more complex way. Maybe the wizards from Harry Potter's world are actually using a form of the mystic arts, but they just don't know it. In fanfiction, Stephen Strange could discover this connection and help the wizards unlock new levels of their magic. This could lead to new spells and abilities for the Hogwarts students.
One interesting story could be where Harry Potter, with his magic from the wizarding world, teams up with Stephen Strange in the multiverse. Maybe they combine their powers to fight a common magical threat that spans across different dimensions. For example, a dark entity that is causing chaos in both the Marvel universe and the wizarding world.