One way is to start with a simple concept like the number of letters in a spell. Let's say you take the spell 'Expelliarmus'. It has 11 letters. You could create a cipher where every 11th letter in a message is the key letter. Then, expand on this by adding more rules based on other Harry Potter elements. For example, if the message is sent during a full moon, you change the order of the key letters according to the phases of the moon. This makes the cipher more complex and believable in the context of the Harry Potter universe.
First, study the existing elements in the Harry Potter world like spells, magical objects, and places. For instance, you could base your cipher on the movement patterns of the Marauder's Map. Then, make sure it fits within the rules of magic already established in the series. Don't create a cipher that goes against how magic works in the wizarding world.
First, give the character a strong motivation. For example, if the character is a scientist, their motivation could be to study Bill Cipher's otherworldly powers. This will drive their actions and reactions when interacting with him. Also, give them flaws. Maybe they're overly curious which sometimes gets them into trouble when dealing with Bill.
First, give the character a backstory. Maybe they come from a family of wandmakers but were always the black sheep, not really interested until something sparked their passion. For example, seeing a unique wand in action at a young age. Second, give them quirks. They could have a habit of always checking the quality of wood by sniffing it. Third, let them have flaws. They might be overly confident in their skills and make mistakes because of it.
First, do research on both the Harry Potter lore and the history of ancient warriors. Understand their cultures, values, and abilities. Then, find a common ground or a conflict point between them. For example, if you're combining the magic of Harry Potter with the Spartans, you could focus on their shared value of courage but also the conflict between magic and brute force. Build your plot around this. Maybe a Spartan - like warrior discovers he has latent magical abilities in the wizarding world and has to adapt.
To create a believable political system, think about the power dynamics between different magical species. In a Harry Potter kingdom building fanfiction, if there are centaurs, goblins, and wizards living together, they would all have different needs and desires. So, the political system should account for how they will be represented and have their voices heard. For instance, goblins could have a say in matters regarding Gringotts and treasure management, while centaurs could be involved in decisions about the use of forested areas.
To create believable characters in Harry Potter NEWTs fanfiction, first, give them real - life flaws. Even the best students might be nervous about exams or have a particular subject they're not good at. For example, a character could be excellent at Potions but struggle with Transfiguration. Second, base their personalities on a mix of the traits we already know from the Harry Potter series. A Gryffindor could be brave but also impulsive in the face of NEWTs stress.
The setting also matters a great deal. In a 'Harry Potter and Pitch Black' fanfiction, you can't just throw the characters together without considering the where and how. If you're setting the story on a planet from Pitch Black, you need to describe it in a way that makes it seem real. How does the magic interact with the strange atmosphere? If it's in the wizarding world, how do the Pitch Black elements disrupt or enhance the normal flow of things? By carefully crafting the setting and how the two universes blend, you can create a believable fanfiction.
Develop their backstories in detail. A character from Ilvermorny might have a family history that is tied to a particular part of American magic. Maybe their great - grandmother was a famous Ilvermorny healer. This backstory can influence their actions and decisions in the fanfiction. They could be driven to follow in her footsteps or rebel against the family legacy. Also, let their relationships with other characters shape them. If a character has a rival at Ilvermorny, it can bring out different aspects of their personality, like competitiveness or a desire to prove themselves.
Start with his background. Decide where he's from, whether it's a pure - blood family, a muggle - born family, or a half - blood family. His family situation will influence his personality and values. For example, if he's from a pure - blood family that has certain traditions, he might be more reserved or have a sense of superiority at first.
Look at real - world mythology and adapt it. For example, take the concept of a mermaid but give it a magical twist like they can control water currents with their songs in a way that affects wizard - made boats. Another way is to combine existing Harry Potter creatures. Maybe a cross between a Hippogriff and a Phoenix, which would have the majestic appearance of a Hippogriff but also the ability to burst into flames and be reborn like a Phoenix.
To create a believable OC in fanfiction, start with a clear backstory. For instance, if it's a medieval - themed fanfic, give your OC a family history that fits the era, like they come from a long line of knights or peasants. Then, give them realistic flaws. Don't make them perfect. Maybe your OC is really good at magic but is terribly shy in social situations. Also, consider their motivation. What drives them? If it's a Hunger Games fanfic, your OC might be motivated by protecting their younger sibling.