For story development, it might be interesting to consider that there is a hidden connection between the two universes all along. In the 'Harry Potter' series, there could be some ancient magic that is related to Noctis' world. When Harry discovers this, he embarks on a journey to find out more. Along the way, he meets characters from Noctis' world, and they start to exchange ideas and powers. This could lead to a whole new series of events where Harry has to use his knowledge of both worlds to save them from a great threat that spans across both universes.
One way it could work is by having Harry Potter be transported to the world of Noctis. He could use his magic skills there and face new challenges that are different from what he's used to in Hogwarts. For example, the magic in Noctis' world might be more elemental - based, and Harry has to adapt to use his wand magic in that context.
One way it could work is if there was a magical portal that connected the wizarding world to Spider - Man's universe. Harry could accidentally stumble through it and then get involved in Spider - Man's battles, using his magic to help out.
One way it could work is if Jack Sparrow somehow ends up at Hogwarts. Maybe he's chasing a magical treasure that has been hidden there. His pirate ways would clash with the strict Hogwarts rules, and Harry Potter and his friends could either befriend him or be suspicious of him. Another possibility is that Harry Potter, being a fan of Jack Sparrow, tries to model some of his actions after the pirate, much to the dismay of his teachers.
One way could be that Godzilla somehow appears in the wizarding world. Maybe a magical experiment goes wrong and transports Godzilla there. Then the wizards and witches have to figure out how to stop it using magic.
One way it could work is by having Harry Potter be a secret admirer of Gomez Addams' unique style and way of life. Maybe Harry discovers some old wizarding texts that mention a connection to the Addams family's magic. He then becomes fascinated and starts to incorporate some of Gomez's traits into his own life, creating an interesting blend of the two worlds.
One way could be that Harry is somehow transformed into a RoboCop - like figure in the wizarding world. He could use his new robotic powers along with his magic to fight against dark wizards. For example, his robotic enhancements could give him super strength to physically combat opponents, while his magic could be used for more complex spells.
Maybe the magic in Harry Potter could be traced back to the primordial gods. For instance, the spells could be seen as gifts from these ancient deities. Harry himself could be a descendant or a reincarnation of a primordial god.
The characters in Harry Potter have clear arcs. For example, Harry starts as an orphan boy and grows into a brave hero. Hermione changes from a know - it - all to a more empathetic friend. Ron overcomes his insecurities. These well - developed character arcs make it great for fanfiction as fans can explore different stages of their growth further.
In this fanfiction, it could be that the magic in Harry's world has a connection to the enchantment on Mjolnir. Maybe the ancient magic that runs through Harry's veins is recognized by Mjolnir's magic as something worthy. So, when Harry tries to lift it, his magic interacts with the hammer's magic in a positive way, allowing him to pick it up.
The character development in such fanfiction often starts with the hybrid's discovery of its own identity. It may struggle between its human - like side (from Harry) and its serpentine nature (from the basilisk).
One way could be to give Harry the Geass power. So, he could use it to control the actions of Death Eaters or Voldemort himself. He might start to make more strategic and calculated moves like Lelouch, using his new power to outwit his enemies. Another aspect could be in the political side. Maybe the wizarding world becomes more like Lelouch's world with different factions vying for power and Harry has to play a political game as well as fight against the dark forces.