One common theme is the struggle against their different natures. Kol is a vampire with a dark past and Davina is a powerful witch. Their relationship often has to overcome the challenges posed by their respective supernatural identities.
One possible plot could be that Kol turns Davina into a vampire out of love. He doesn't want to lose her to mortality. Davina, at first, is horrified as she has always been on the side of the witches. But as she starts to experience her new vampire powers, she begins to see the world in a different light. She and Kol then have to face the wrath of the witch community who see her transformation as a betrayal.
Their relationship would become more intense. As a vampire, Davina would have new emotions and instincts. Kol, who has more experience as a vampire, would have to guide her. This could lead to some power struggles as Davina is used to being in control. But it could also bring them closer as they face new challenges together.
For Davina, she would become more cautious. As a mother - to - be, she would no longer take risks as easily. Her focus would shift from just her own powers and place in the supernatural world to protecting her unborn child. Kol, being the father, would likely become more responsible. He has a bit of a wild streak, but the pregnancy would make him think twice before getting into dangerous situations.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions on various topics, including Kol and Davina as soulmates. Just use the search function and type in 'Kol and Davina soulmates' and you'll likely find many interesting stories.
One possible plot could be that Davina and Kol discover the pregnancy unexpectedly. They might face many challenges. For example, they would have to deal with the reactions of their families and friends in the supernatural world. Some might be happy, while others could be worried about the implications of a half - witch, half - vampire baby. Also, they would need to protect the unborn child from the many threats in their world.
One common theme is the power struggle. Given Klaus's powerful vampire nature and Davina's strong magic, there's often a play of power between them. Another theme is redemption. Klaus is often seen as a villain, and in some fanfictions, Davina helps him find a path to redemption.
One common theme is the idea of redemption. Kol is often portrayed as a character in need of redemption, and Bonnie can be the one to help him. Another theme is forbidden love. Since they come from different sides in the show's lore, their relationship can be seen as something that is not supposed to happen.
They could develop a shared hobby. For instance, they both get into painting and use it as a way to express their emotions and connect on a deeper level. It would be unique because it shows a side of them that's not related to their supernatural natures.
One popular klaus and davina fanfiction is 'A New Bond'. It delves into their relationship in a really interesting way, exploring how their different personalities interact. It has some great dialogue that really brings the characters to life.