Character development is crucial. If you're crossing over with the Lord of the Rings, show how the Elric brothers would react to the different races in Middle - earth. They might befriend the hobbits or be in awe of the elves' wisdom. Their personalities should change and grow as they interact with new characters and face new challenges. Also, make the conflict believable. If there's a new enemy that threatens both universes, it should be something that couldn't be easily defeated by either world's normal means.
First, you need to understand the rules of both universes involved. For example, if it's a crossover with Star Wars, you have to know how the Force works in Star Wars and how alchemy functions in Full Metal Alchemist. Then, find a common ground. Maybe there's a similar power source in both worlds that can be the starting point for the plot. Like a dark energy in Star Wars and a corrupt form of alchemy in Full Metal Alchemist.
Writers should first understand the core characteristics of Envy. Know that Envy is a very vengeful and envious character. So, when creating a crossover plot, make sure Envy's actions are driven by these traits. For example, if the crossover is with a fantasy world where there are powerful magical items, Envy might be envious of those who possess them and try to take them. Also, keep the rules of both universes in mind. If in the other universe, magic has certain limitations, don't break those rules when Envy interacts with it. This will make the plot more believable.
First, research both universes thoroughly. Know the capabilities of the Halo Spartans, their weapons, and the political situation in their world. Similarly, understand the powers, backstories, and relationships of the Overwatch characters. Then, find a common ground for them to interact. It could be a threat that affects both universes or a shared goal like exploring an ancient artifact that has significance in both worlds.
Research the uke concept and find ways to integrate it into Naruto's world. If the uke is often seen as a more submissive role, Naruto could be forced into that role due to some sort of magic or new social order. But he could still fight against it in his own Naruto - like way. You could also introduce new characters that are key to the uke - Naruto dynamic, like a powerful antagonist who misinterprets Naruto as weak because of the uke - like situation.
First, study the lore of both games. Know the rules of how powers work, the social structures in each world, etc. Then, find a common ground. Maybe it's a shared threat like a powerful, otherworldly entity that is attracted to the unique energy signatures of the powers in both universes. Make sure the characters' actions are in line with their personalities. For example, Cole is often driven by a sense of justice, so he would likely approach a situation differently than Alex, who has more of a survival - of - the - fittest mentality.
To create a believable plot, first, you need to understand the lore of both Kitsune and Naruto. For example, Kitsune are known for their trickery and magic. You could incorporate this into the story by having a Kitsune character play tricks on Naruto and his friends, but in a way that ties into the overall plot, like leading them to a hidden power or a secret enemy.
First, understand the core elements of both Big Hero 6 and the other crossover element. For example, if it's a crossover with a magical world, find a way to make the science - based technology of Big Hero 6 interact with magic. Maybe a magical event disrupts the technology in San Fransokyo, and the team has to find a way to fix it with the help of the new crossover characters. Second, develop character relationships. Show how the characters from both worlds react to each other, whether it's with suspicion or immediate friendship. Third, have a clear goal for the story. It could be to save both worlds from a common threat or to solve a mystery that involves both universes.
To create a believable plot, first, you need to establish the rules of the nazi zombies world clearly. For example, how are they created, what are their weaknesses? Then, when introducing characters from other universes or stories, make sure their abilities and personalities are consistent. If a character is known for being brave and resourceful in their own world, they should act that way in the crossover. Also, give a good reason for the crossover to happen, like a magical portal or a scientific experiment gone wrong.
One idea could be a crossover with the Harry Potter universe. Edward and Alphonse could attend Hogwarts and learn about magic while also trying to find a way to use alchemy in that world. Maybe they'd be interested in the Philosopher's Stone in the Harry Potter series, which has similarities to the concept of the Philosopher's Stone in Full Metal Alchemist.
To create a believable plot, start with a simple premise like an SCP escaping into the Fate/GO world. This SCP could start causing chaos, and the Servants would be the ones with the power to stop it. But as they try to deal with it, they discover that the SCP has some strange connection to the Grail or the Servant summoning system. For example, the SCP might be able to absorb Servant energy. As the plot progresses, the characters would have to make difficult decisions. The Masters might be tempted to use the SCP's power for their own gain in the Grail War, while the Servants would have to decide whether to follow their Masters or do what's right.
To create a believable plot, think about the characteristics of spiders and how they can be incorporated into the Harry Potter world. Spiders are often associated with mystery and hidden places. So, in the fanfiction, the spiders could live in a hidden part of Hogwarts that no one knew about. Harry Potter accidentally discovers this place. The spiders there have a prophecy about a wizard who will save them from a great danger. They believe Harry is that wizard. But there are also other forces at work, like some Slytherin students who want to use the spiders for their own dark purposes. This creates a complex web of relationships and conflicts that make the plot believable.