The lore of the Transformers must be respected. You can't just make up random rules about how Cybertron works. Make sure you understand the different factions, their goals, and the technology involved. This helps in creating a believable crossover story.
Plot is also very important. Since it's a crossover, there should be a good reason for the OC to enter the Transformers world. It could be an accident, a scientific experiment gone wrong, or a quest. Then, build a story around how the OC interacts with the existing characters and changes or is changed by the events in the Transformers universe. For instance, they might help the Autobots find a new energy source or get caught in the middle of a battle between the two factions.
Character balance. You need to make sure that no single character from either cartoon overpowers the others in the war scenario. For example, if you cross over 'Powerpuff Girls' and 'Ben 10', you can't let Ben 10's alien forms completely dominate the fight against the Powerpuff Girls.
The lore of both universes has to be respected. The different rules about vampires, werewolves, and Blade's unique origin all need to be incorporated correctly. You can't just mix things up randomly. A good understanding of the mythology in both Blade and Underworld is essential. And also, the plot should be engaging. Maybe create a new threat that forces the characters from both worlds to interact, like a super - powerful hybrid creature that neither side can defeat alone.
Character consistency is crucial. Django has a certain set of values and a backstory that should be respected. If you're crossing over with another character, like say Indiana Jones, you need to make sure that Django's actions and reactions are in line with his personality from 'Django Unchained'.
Themes. In a Mars Attacks crossover with 'The Hunger Games', you could explore themes of power, survival, and rebellion. The Capitol could see the Martians as a new way to control the districts, or the districts could team up with some Martians (if possible) to overthrow the Capitol. It's about finding common themes between the two universes and building a story around them.
The plot should tie into the existing Arkham Knight storylines. You can't just create a completely separate story. Maybe your OC is affected by the actions of the main characters like Batman or the Arkham Knight. Interaction with the known characters is also important. Their reactions to the OC should be believable based on their established personalities in the game.
One key element is character consistency. Your OC should fit into the world of Miss Kobayashi without feeling out of place. Their behavior, values, and abilities should be in line with the overall tone of the series. Another element is world - building. Even though it's fanfiction, you can expand on the existing world. For example, if your OC is from a far - off dragon land, describe what that place is like. Also, the relationship between your OC and the main characters is crucial. It should be believable and add something new to the story. For instance, if your OC is Kobayashi's new coworker, how does that change her daily interactions?
The plot should be engaging. You can create a common enemy that only the combined powers of Gaim and the other Kamen Rider can defeat. This gives a reason for their crossover. Or you could explore a mystery that spans both of their worlds, like a strange phenomenon that is affecting both the fruit - filled world of Gaim and the high - tech world of another Kamen Rider. This way, readers will be interested in seeing how the two Riders work together to solve the problem.
One key element is character design. Your Jesus OC should have characteristics that are both in line with the traditional image of Jesus and also fit into the Highschool DxD world. Another important aspect is the power system. Decide how his powers will work and interact with the existing power dynamics in the story. Also, think about the relationships he will form. Will he be friends with the devils, angels, or both? And finally, the theme of the story. It could be about redemption, friendship, or the struggle between good and evil in this unique setting.
First, the servant's backstory is crucial. It should be well - thought - out and fit within the lore of the Fate Zero universe. For example, if the servant is from a certain historical period, the details should be accurate. Second, the servant's abilities. They need to be balanced and not overly OP. Third, the interactions with the existing characters. It should feel natural and add something new to the story.
Character design is crucial. The male oc should have distinct traits, like a unique fighting style or a special personality quirk. For example, he could be a very laid - back character who uses his calmness to his advantage in battles. Also, his backstory needs to be well - thought - out. Maybe he has a past connection to the life fibers that is yet to be discovered.