Well, in some fanfictions, Charlie might use his dragon - handling skills to protect Harry. For example, he could train dragons to guard Harry or use his knowledge of magical creatures to fend off threats that are related to dark magic and its associated beasts.
For Harry, the author can show his vulnerability. He's used to being the hero, but now in this new situation, he has to rely on others more. He might be scared at times, but also determined to see this through for the sake of the baby. Charlie, on the other hand, can be developed as a very supportive partner. He might have to learn quickly about taking care of Harry, like making sure he eats well and gets enough rest. He could also be shown as someone who is protective, not just of Harry but also of the new life they are about to bring into the world.
They could be like brothers. Harry has a strong connection with the Weasley family already, and with Bill and Charlie, it could be a natural extension of that. They might look out for each other and support one another in any difficult situation.
Charlie could use magic to simply apparate Harry away from the Dursleys' house. It's a quick and efficient way to get Harry out of that horrible situation.
Overcoming differences is also a theme. Since they are two distinct characters, they may have different personalities or beliefs. Fanfictions often show how they learn to accept and work with each other's differences, which can be really inspiring for readers.
I'm not entirely sure specifically what a 'harry charlie slash fanfic' is about without more context. 'Slash' in fanfic often refers to a romantic or sexual relationship between two male characters. So it might be a fan - created story about a relationship between characters named Harry and Charlie.
One great 'Harry and Charlie Swan Fanfiction' is 'The Unlikely Bond'. It beautifully weaves their characters together in an alternate universe where they team up to solve a mystery in Forks. The story has a great balance of character development and plot twists.
There could be. The world of fanfiction is vast and diverse. Writers take the characters from existing works and put them in new and unexpected situations. The concept of Harry and Charlie as soulmates gives a lot of room for creativity. It could involve exploring their different personalities, how they meet in a different context than the original story, and how their relationship develops over time. However, it also depends on the popularity of the specific pairing within the fanfiction community for a particular fandom. Some pairings are more common and thus have more stories written about them, but that doesn't mean this one doesn't exist. Check the major fanfiction sites.
A fem Harry x Charlie pregnancy fanfiction could explore different themes. For example, it could focus on the reactions of their friends and family. Maybe Harry's friends from Hogwarts are shocked but supportive. Charlie, being a dragon keeper, might have his own concerns about bringing a child into a world where his job is so dangerous. It could also show how they adapt to their new roles as parents - to - be.