You should start with research. Read a lot of existing fanfiction to get an idea of what works and what doesn't. When it comes to actually writing, start small. Write a short scene where two characters from different universes meet for the first time. Build on that, adding more elements of the crossover as you go. Don't be afraid to take risks and be creative with your ideas, but also make sure it stays true to the essence of both the MGSV world and the other world you're crossing with.
Another example could be a crossover with 'Final Fantasy'. The magic and fantastical elements of Final Fantasy could be blended with the gritty realism of MGSV. Maybe a character like Cloud could find himself in the middle of a mission in the MGSV world, and his sword - fighting skills and limit breaks could add a new dynamic to the combat scenarios.
To start writing a chara crossover fanfiction, you should start with brainstorming ideas for how the characters will interact. Will they be friends or foes at first? Also, think about how the different rules and worlds of the original characters will blend or clash. For example, if you're crossing a magical character with a non - magical one, how will that work? Sketch out a rough outline of the story, including the beginning, middle, and end. You can start with a simple premise like 'What if these two characters met?' and then build on it. Consider the character arcs for each of the crossed - over characters. How will they change during the story?
Begin by brainstorming ideas. Think about what would happen if the 'legion' met a different group of characters. You can draw inspiration from other crossover fanfictions you've read or movies/TV shows you've seen. After that, develop your characters. If you're bringing in characters from different universes, give them new dynamics. They might be initially suspicious of each other but then learn to work together. And don't forget to set the scene. Describe the new world that is created by this crossover, whether it's a mix of the 'legion' world and another or a completely new place where they all end up.
To start writing 'Battletech Crossover Fanfiction', begin by choosing a crossover that has potential for great stories. Say you pick 'Battletech' and 'Full Metal Panic'. Research both universes thoroughly. Next, create a strong plot. Maybe the mechs are being used in a war on a planet similar to the one in 'Full Metal Panic'. Develop your characters well, like how a Battletech pilot would react to the situations in the other universe.
Begin by exploring the personalities of Robin and the character he is crossing over with. If it's, say, Robin and Supergirl, understand how Robin's detective skills and combat training would interact with Supergirl's superpowers. You can start with a small encounter between them, like they meet by accident and then gradually build up to a bigger adventure. Also, don't forget to add some conflict, whether it's internal (Robin struggling with his own insecurities) or external (facing a powerful enemy).
Begin by creating a character profile for Android 21 in this new crossover setting. Consider her goals and how they might change. Also, establish the rules of the new world she's in. If it's a world of magic, how will her powers interact with magic? You can start with a simple scene, like her arrival in the new world, and build from there.
Begin by brainstorming interesting scenarios. If you're doing an 'It' crossover with a sci - fi story, think about how the otherworldly elements of 'It' like the sewers and Pennywise's powers would work in a sci - fi setting. Decide on your main characters from both universes. Then, create a rough plot outline. You could start with a character from one world stumbling into the other. It's all about being creative and having fun with it.
First, decide which two universes you want to cross over. For example, if it's Little Nightmares and Alice: Madness Returns, study the lore and characters of both. Then, create a scenario that brings the characters together, like a strange portal opening up.
First, decide on the two (or more) universes you want to cross over. For example, if it's Digimon and Naruto. Then, think about how the characters from each universe will meet. It could be something like a strange portal that transports a Digimon to the Naruto world. Next, consider the personalities of the characters and how they'll react to each other. A Digimon might be confused by ninjas at first. Then just start writing, describe the scene where they meet and let the story unfold from there.
You should also focus on character development. If you're crossing with the Fullmetal Alchemist world, consider how Chrollo would interact with the Elric brothers. He might see their search for the Philosopher's Stone as something he can use for his own purposes. Start with a small scene that sets the tone, like Chrollo arriving in Amestris and observing the alchemic practices there, and then build the story from that initial encounter.