To blend the universes well, start with a believable crossover event. It could be a portal opening between the two worlds. Then, focus on character interactions. Let the heroes from both sides exchange ideas about heroism. For example, Green Lantern and Tsuyu Asui could discuss their different ways of using their powers for good.
One way to combine them is through a crossover story. Imagine characters from My Hero Academia being transported to the Justice League's universe. For example, Deku could meet Superman and learn about a different kind of heroism. Their powers and ideologies could clash or complement each other. Another aspect could be the villains. The League of Villains could team up with some of the Justice League's foes, creating a huge threat that both groups of heroes have to face together.
In this fanfiction, the social hierarchies of both worlds would come into play. The Justice League has a more hierarchical structure with established leaders like Superman. In My Hero Academia, there are hierarchies within the hero schools and the hero society. When the characters interact, they would have to navigate these different power structures. For instance, the students of U.A. might be in awe of the Justice League members at first, but then they would learn that they too have their own strengths and can contribute equally. This would change the way the characters interact and respect each other.
Well, you could start by finding a common theme. For example, both could involve a sense of journey or a sequence of events. In 'This Little Piggy', there's a sequence of the piggy going to the market, staying home, etc. In the Justice League, there are often sequences of battles or quests. You can mirror these in the fanfiction.
The fanfiction could involve power - sharing or power - swapping scenarios. Imagine if All Might had the power of Green Lantern for a while. How would he use it? Or if Wonder Woman had One For All. This would not only create interesting battle scenes but also explore the characters' personalities in new ways. Also, the different power levels in the two universes could be equalized in creative ways. For instance, the lower - powered characters in My Hero Academia could find ways to hold their own against the super - powerful Justice League members through strategy and teamwork.
A darker plot idea could involve a powerful villain who has somehow found a way to corrupt both universes. This villain uses the technology and powers from both My Hero Academia and the Justice League's worlds to create a doomsday scenario. The heroes must put aside their differences and combine their strengths to stop this new threat. This would involve a lot of character development as they learn from each other's methods of heroism and sacrifice.
A cool fanfiction idea could be a team - up between specific members of the Justice League and My Hero Academia characters. For instance, The Flash and Izuku Midoriya could compete in a race, with Izuku learning about speed and the Flash learning about the concept of 'One For All'. This would not only be an exciting story but also a great way to explore the different power dynamics and personalities of the two universes.
One way to combine the My Hero Academia and Avengers universes in a fanfic could be through a dimension - hopping plot device. Maybe a character from My Hero Academia accidentally discovers a portal to the Avengers' universe. For example, Deku could find himself in New York City and meet Iron Man. Iron Man, being the genius he is, would be intrigued by Deku's Quirk and want to study it. This could lead to an exchange of ideas and technology between the two universes, like Deku learning about Stark technology and using it to enhance his hero suit in his own universe.
In many fanfictions, it blends the two worlds by having Ranma enter the My Hero Academia universe. His martial arts skills become like a unique quirk in that world. For example, his ability to change gender due to the curse can be seen as a strange quirk that others are both curious and confused about.
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.