The fanfiction could also take a more mysterious turn. Perhaps their sickness is not a normal illness but something that was cursed upon them. There could be a villain in the story who has targeted them specifically. The other characters, like Bella or Edward, might get involved to help find a way to break the curse, adding an interesting crossover element to the Twilight - based fanfiction.
It could be due to a magical or supernatural influence in the Twilight universe. Maybe a dark witch cast a spell on them, as there are many supernatural elements in the Twilight world.
It changes it a great deal. For one, it adds a new layer of complexity to Bella's relationships. Instead of just the Edward - Jacob love triangle, now there are Jared and Paul involved. It also affects the werewolf pack dynamics as their loyalty and actions are now tied to Bella in a different way.
One challenge could be the acceptance from the two different communities, the werewolves and the vampires. Another might be the safety of Bella during the pregnancy, as it could attract unwanted attention. And of course, there's the relationship between Paul and Bella, which may face strain due to the sudden change in their situation.
In addition to them, there could be other characters from the original series that play supporting roles. For example, other members of the wolf pack might be involved, either helping Paul and Jared or being skeptical about their imprint on a human girl. And there could also be Bella's human friends who notice the strange changes in her life because of this new relationship with Paul and Jared.
They are popular because they show a different side of Twilight. Usually, she is seen as the smart, in - control character. When she's sick, she becomes vulnerable, and readers like to see how she and her friends handle this new situation.
One popular one might be 'Twilight's Sick Day' where all her friends come to take care of her in their own unique ways. For example, Pinkie Pie tries to cheer her up with her wild parties, but quickly realizes Twilight needs peace and quiet. Another could be 'When Twilight Fell Ill' which focuses more on Twilight's internal struggle with being sick and not being able to study or do her normal princess duties. It shows how she has to rely on her friends more than ever.
One common theme is the exploration of forbidden love. Since Bella is mainly associated with Edward in the original series, a relationship with Jared is considered outside the norm, creating a sense of forbidden attraction.
Themes of love and loyalty are often central. Kim and Jared's relationship may be tested by the various challenges in the Twilight universe. Their love could be a source of strength or a cause of conflict. Also, loyalty to their friends, families, and respective groups (if they belong to any in the fanfic) is explored. This can lead to some really interesting plot twists and character development as they balance their personal feelings with their duties or allegiances.
Yes, there are quite a few. You can start by looking on popular fanfiction websites like FanFiction.net or Archive of Our Own. Some of them explore unique relationships between Bella Swan, Paul Lahote, and Jared, often delving into the complex werewolf lore from the Twilight series and creating interesting storylines around their interactions.