He could be a valuable asset. His immortality means he has a vast amount of experience. He could use his magic to heal the injured members of the League quickly. For instance, with a spell like 'Episkey', he could mend wounds in seconds.
It could be a wild and exciting story. Maybe the wizards from Harry Potter team up with the super - heroes of the Justice League. The immortals in the story could be Dumbledore or Voldemort from Harry Potter world, and they bring their magic to the Justice League's fight against evil. It would be a clash of different powers and cultures.
One interesting crossover could be Harry using his magic in the world of the Justice League. For example, he could use spells like 'Accio' to retrieve important items during a Justice League mission. Maybe he'd team up with Superman and use magic to enhance Superman's powers in a unique way.
A fanfiction like this would blend elements in many ways. First, the settings would merge. Hogwarts could exist in the same universe as Metropolis or Gotham. The characters would exchange their skills. Batman could learn some magic tricks from the Potter characters. The concept of immortality could be a unifying factor. The immortals in the Potter world might have a different view on life and death compared to the superheroes. This could lead to philosophical discussions within the story, as well as new ways of approaching battles and solving problems.
Yes, there are quite a few. You can start by looking on fanfiction websites like Archive of Our Own or FanFiction.net. Just search for the key terms 'Harry Potter Justice League Harem' and you'll likely find some interesting reads. However, the quality can vary greatly, so it might take some time to find one that really suits your taste.
Another concept is that the magic from the Harry Potter series starts to seep into the DC universe where the Justice League operates. This causes chaos as the laws of physics in the DC world are disrupted. The Justice League has to seek help from Hogwarts professors to understand and contain this new form of magic energy. Superman might be intrigued by the idea of magic being a new power source or a new threat he can't easily overcome with his super strength.
One way it could work is by having the magical elements of Harry Potter in the Justice League universe. For example, the wizards could help the Justice League with their spells in battles against powerful foes. Maybe Harry Potter himself could use his Patronus charm to fend off some of the League's enemies like Darkseid's minions.
It could be a wild adventure where Harry Potter, with his magical abilities, teams up with the Justice League. Maybe Harry uses his spells to enhance the League's powers or to combat enemies that are immune to their usual tactics. For example, he could use a Patronus charm to fend off some dark, mind - controlling villains that the League has trouble with.
Well, in a fanfiction where Harry Potter joins the Justice League, there would be some interesting interactions. Harry's knowledge of the magical world could help the Justice League deal with threats that have a magical or otherworldly origin. His experience in fighting dark wizards might give the team new strategies. Also, the members of the Justice League would probably be fascinated by his magic, and there could be some funny moments of them trying to understand how it all works.
A really cool crossover concept could be a combined threat that requires both the skills of the Justice League and the magic of the Harry Potter world to defeat. Maybe a powerful alien sorcerer arrives on Earth. The Justice League's superpowers alone aren't enough, so they team up with Harry Potter and his friends. Harry could use the Patronus charm to fend off the dark magic of the alien, while the Flash could use his speed to quickly deliver magic items to different locations as needed.