A crossover could function through a portal or some sort of magical event that links the two worlds. For instance, the Tesseract in the Avengers universe could malfunction and open a portal to the Harry Potter world. Then, the Avengers find themselves in a world full of magic and wizards. They soon learn about the God of Death and realize that they need to work with the wizards like Harry, Hermione, and Ron to stop this ultimate force. The Avengers' powers would be a new and strange thing in the Harry Potter world, and the wizards' magic would be equally fascinating to the Avengers.
In a crossover fanfiction, the characters' personalities would play a big role. Harry Potter is brave and selfless, much like Captain America. So, they could lead their respective teams. The God of Death could be lured out by the power of the Infinity Stones and the Deathly Hallows combined. The Hulk could be used as a powerful force against the minions of the God of Death, while Hermione's intelligence could be used to figure out a way to defeat the God of Death on a more strategic level. And Thor could share his knowledge of gods and otherworldly beings with the wizards to help them understand the true nature of the God of Death.
The concept could work by having Harry bring the magic of the wizarding world into the Avengers' realm. His knowledge of potions could be used to create elixirs that give the Avengers new abilities. He could also use his wand to control the elements, like Thor does with his hammer, but in a more magical way. This would make him a valuable and almost god - like addition to the team.
One way a Death Note and Harry Potter crossover could work is by having a Death Note fall into the wizarding world. Maybe a Muggle - born student discovers it and starts using it to deal with dark wizards in secret. However, they soon realize the moral and ethical implications are just as complex as in the original Death Note story.
It could work if the Infinity Stones and the Deathly Hallows had some sort of connection. Since Harry is the Master of Death, he might be sensitive to the power of the Stones. The Avengers are dealing with the Stones' power, and Harry could bring his knowledge of dealing with powerful magical artifacts from his world. He could teach the Avengers about the consequences of misusing powerful items and how to safeguard against the corrupting influence of such power.
Well, it could work by having a common threat. Say a powerful sorcerer from the Harry Potter world who has learned to harness some sort of high - tech power similar to what the Avengers deal with, and also has a network of assassins at his command. The heroes from each world would then come together. Harry Potter and his friends would bring magic, the Avengers their superpowers and technology, and the Assassin their unique combat and stealth abilities to combat this threat.
Well, it could work by having the magic from Harry Potter interact with the brutal combat of God of War. For example, Harry could use his spells against the mythical creatures from God of War. Maybe he'd face off against a minotaur and use the Stunning Spell to stop it in its tracks. The Portkey could also be a way to transport characters between the two worlds. And the Elder Wand could be a super - powerful weapon in the God of War universe, with its own unique abilities that could give an edge in battles against the likes of Kratos.
One idea could be that the Deathly Hallows from Harry Potter have some sort of connection to the powers of the God of Death in the Avengers universe. Maybe the Elder Wand could be a weapon that has the power to control the souls like the Infinity Stones do in the Avengers. The Invisibility Cloak could be used by a character from the Avengers to sneak around in a world filled with magic, similar to how Harry used it at Hogwarts.
Well, a simple way could be through a portal. Imagine a magical portal opening between the mutant world and the wizarding world. Magneto steps through and is immediately in Hogwarts. The students and teachers are both fascinated and terrified. Harry Potter, being the brave one, approaches Magneto to find out his intentions. This encounter could spark a whole series of events where they either become friends or enemies depending on how Magneto reacts to the wizarding world's power structure.
Well, perhaps the lawyer character could be a Muggle - born in the Harry Potter world who is a huge Avengers fan. They somehow end up in a situation where they have to use their lawyering skills to represent the Avengers against some sort of magical - technological threat that combines elements from both universes. They might argue about who has the right to certain magical artifacts that are now in the hands of tech - savvy villains.
In a crossover, a female Harry Potter could be like a new recruit to the Avengers. She would start off being a bit of an outsider, but gradually earn their respect. Her magic would seem strange to the Avengers at first, but they would soon realize how useful it could be. She could help with things like getting into secure places that are protected by magic - like barriers in the Marvel universe that normal means can't penetrate. And she could also use her Patronus charm to inspire and protect the team during tough battles.
One way it could work is through the concept of alternate universes. In a Marvel - Potter crossover fanfic, the power of being the Master of Death could be seen as a sort of super - power. Harry could use his mastery over death to perhaps revive fallen heroes in the Marvel universe, like bringing back Bucky Barnes before his resurrection in the main storyline. This would create a whole new dynamic and set of relationships.