One way to blend the Mortal Kombat and Harry Potter universes in fanfiction could be through a magical portal. Imagine a portal opening between Hogwarts and the Mortal Kombat realm. Harry Potter characters could be drawn into the Mortal Kombat world and have to adapt to its brutal fighting style. They might use their magic in unique ways during the Kombat tournaments. For example, Hermione could use her vast knowledge of spells to create new combat spells inspired by Mortal Kombat moves.
Another strong contender could be Raiden. As a thunder god in Mortal Kombat, he has control over lightning and has great combat skills. In the Harry Potter universe, his lightning attacks could be very difficult to defend against. He could also use his powers to disrupt magic, as electricity can interfere with magical devices. His immortality also gives him an advantage, as he can keep coming back in a fight no matter how much damage he takes.
Perhaps a spell gone wrong in the Harry Potter universe could open a portal to the Back to the Future universe. Hermione, being the brilliant witch she is, could team up with Marty McFly. They would have to learn about each other's worlds quickly. Hermione could teach Marty about magic, and Marty could show Hermione how to use the flux capacitor. Together, they could face challenges in both universes, like stopping Biff from taking over Hill Valley in the Back to the Future world and defeating Death Eaters in the Harry Potter world.
One way to blend the two universes in fanfiction could be through a magical accident. For example, a spell in the Harry Potter world could go wrong and open a portal to the God of War realm. This would allow characters from both to interact. Harry Potter characters might be shocked by the brutal and violent nature of the God of War world, while Kratos could be intrigued by the magic in the Potterverse.
One way is to have characters from My Hero Academia attend Hogwarts. For example, Izuku Midoriya could be a new student at Hogwarts, learning magic instead of using his Quirk. His determination and growth mindset would fit well in the magical world. He could make friends with Harry Potter and his gang, and they could learn from each other. Midoriya's strategic thinking from his hero training could help in battles against Voldemort's forces, while the wizards could teach him about magic spells that might be equivalent to his Quirks in some ways.
Well, a simple way is to have a plot where the villains from both worlds team up. In this case, the Death Eaters and some of the powerful villains from My Hero Academia like All For One could form an alliance. The heroes from both universes would then have to come together to fight this combined threat. It would be interesting to see how the heroes with quirks interact with those who use magic to combat this new, powerful enemy. For instance, Bakugo might initially be dismissive of magic but then learn to respect it as he sees its power in battle.
One possible scenario in this fanfic could be female Harry Potter having to adapt to the brutal and different combat rules of Mortal Kombat. Maybe she would bring some of her magic skills into the Kombat world and use them in unique ways against the Mortal Kombat fighters. For example, she could use a spell to disarm an opponent or create a shield to block attacks. It would be really interesting to see how her Hogwarts training would fare in this new and deadly environment.
One interesting crossover could be the magical spells from Harry Potter being used in the Mortal Kombat arena. For example, a wizard could use the 'Stupefy' spell to stun an opponent before delivering a finishing move. Another aspect could be the Hogwarts students training in Mortal Kombat style combat to defend themselves against dark wizards.
Some fanfictions might explore the idea of a Mortal Kombat tournament taking place at Hogwarts. The various Mortal Kombat characters would bring their own brand of combat, while the Hogwarts environment would add a magical twist. The students could either be spectators or get involved in some way. This would mix the high - stakes, often gory combat of Mortal Kombat with the more whimsical and magical world of Harry Potter.
The most interesting aspect is the clash of two very different universes. Harry Potter is all about magic, friendship, and good vs evil in a more 'fantasy - adventure' style. Mortal Kombat is known for its brutal and intense fighting. When combined, we get to see how the magic users would fare in a Mortal Kombat - style fight. For example, would Harry's Expelliarmus work against Scorpion's spear? It's really exciting to think about.
Another aspect could be the fusion of their worlds' elements. In Mortal Kombat, there are dark and hellish realms, while Naruto has its own unique elemental chakra system. A fanfiction could explore what would happen if the dark magic from Mortal Kombat's realms seeped into the Naruto universe and affected the chakra. Maybe it could create new types of jutsu or even corrupt some of the ninja. It would be a great source of conflict and adventure in the story.