Often, there is a theme of self - discovery. Bella, who is still trying to figure out her place in the vampire - werewolf world, can use her relationship with Jasper as a way to learn more about herself. Jasper, too, might discover new aspects of his personality through his connection with Bella. This theme of self - discovery adds a lot of depth to the characters in the fanfiction.
One common theme is the exploration of an alternative relationship. Since in the original 'Twilight' series, Bella is mainly focused on Edward, fanfictions often look at what could happen if she had a stronger connection with Jasper. Another theme is the power dynamic. Jasper's ability to control emotions and Bella's resistance to it can create some really interesting scenarios.
One common theme is the exploration of forbidden love. Since Bella is initially with Edward in the Twilight series, her relationship with Jasper in fanfiction often treads on that territory. Another theme is self - discovery. Bella may discover new sides of herself through her interactions with Jasper. Also, the theme of loyalty is often explored, as Jasper and Bella have to consider their loyalties to the Cullen family and to each other.
Friendship is also a major theme. Since they are part of the same 'vampire family', many fanfictions develop their friendship. This could include them sharing secrets, going on adventures together, or just having deep conversations about their existence as vampires and Bella's transition from human to vampire.
Another theme is the power dynamic. Jasper has his special abilities and Bella has her own charm. Fanfictions may play with how these two aspects interact and influence each other. For example, in some stories, Bella's humanity affects Jasper's view on his vampiric nature.
A prevalent theme in jasper and bella fanfiction is the struggle against the odds. They come from different backgrounds and have different natures within the Twilight universe. Fanfictions often focus on how they overcome these differences. Also, themes of loyalty and sacrifice are common. They might be in situations where they have to be loyal to each other and make sacrifices for their relationship or for the greater good of their vampire - human world.
One common theme is friendship. They often have to learn to trust and rely on each other.
Another theme is the impact on the Cullen family dynamic. Their relationship, if they are related, can change the power balance and the way the family functions. It can also cause tensions or bring new understandings among the family members.
One common theme is the exploration of love triangles. Since Edward, Jasper, and Bella are all in an interesting dynamic, many fanfictions focus on how their relationships could be reimagined in different ways regarding love and attraction.
One common theme is the exploration of an alternative relationship. Since in the original Twilight, Bella is mainly with Edward, fanfictions often look at what could happen if she had a closer bond with Jasper. Another theme is the power dynamic. Jasper has his unique ability to control emotions, and this often plays a role in how he and Bella interact in these stories.
One common theme is the exploration of forbidden love. Since Jasper has his own complex backstory and Bella is human, their relationship often faces various obstacles that make their love seem forbidden.
One common theme is protection. Since Bella is often in a vulnerable state as a baby, Jasper is usually portrayed as her protector. For example, in many stories, he guards her against various threats in the vampire world.