Friendship is a very common theme. Writers often explore how Caroline and Kate support each other through thick and thin. Another common theme is growth. They might show how the two characters grow and develop as individuals while being in each other's lives.
There is a fanfiction titled 'Caroline and Kate's Secret'. In this story, they share a secret that binds them closer. It's full of mystery and drama. Also, 'Caroline, Kate and the Mysterious Event' is quite engaging as it throws them into a situation where they have to solve a mystery using their unique skills and bond.
Love and friendship are common themes. Writers often explore the relationship between Caroline and Kate, whether it's a budding romance or a deep platonic bond.
I'm not sure specifically which Caroline Kate fanfic is the best as it depends on your taste. But you could start by looking at fanfic communities and forums where fans discuss their favorite Caroline Kate fanfics. They often share links and give reviews, which can be a great way to discover some hidden gems.
Secondly, create a vivid setting. Since it's set in Halifax, describe the place well - the streets, the buildings, the weather. It can add a lot of atmosphere to your story. Also, think about the time period and how it affects the characters' lives.
Caroline as a human in fanfiction with Klaus can create a really interesting dynamic. It allows for exploration of how a human might interact with a powerful vampire like Klaus. For example, she could be a source of light in his dark world, constantly challenging his views.
Another plot could involve a mystery that Caroline and Kate have to solve together. It could be something related to the history of Halifax. As they dig deeper into the mystery, their bond grows stronger. They might have to face some difficult decisions during the process, which would test their relationship.
Another possible ally could be an older vampire who has a different view on the power struggles among the original vampires. This vampire might see something special in Caroline and decide to help her navigate the complex and often dangerous world of the original vampires.
There's also 'The Unlikely Bond'. This fanfiction delves deep into how Caroline and Klaus might interact outside of the main plot of the show. It shows their different personalities clashing and then gradually coming together in a really engaging way. It's full of great dialogue and some really sweet moments between them.
There's not enough information given to know exactly who Caroline is. She could be the main character, a sidekick, or just a minor character in the Sapphire Pokemon fanfiction.