One possible theme could be wealth. Since it's a diamond city, wealth would be a prominent aspect. The story might explore how people are affected by extreme wealth, whether it makes them greedy or more generous.
One possible theme could be about discovery. If Abagail King is on a journey to find the diamond, it could be about the discovery of something precious and what that means.
Another theme might be the contrast between rural and urban life. If Maedon is from a different place, the story could explore how the city is different. It could also be about friendship. Maedon may meet various people and form deep friendships in the city.
A theme of transformation could be in a 'a bull city story'. For instance, if the city was once a small rural area relying on bull - driven agriculture and then transformed into a modern metropolis, the story could show how the relationship with bulls changed over time. This could involve changes in how the bulls were used, how they were perceived, and what role they played in the city's evolving identity.
One possible theme could be self - discovery. As Claude navigates the city, he might learn more about himself. Another theme could be urban vs rural, if Claude is from a different kind of place.
A third possible theme could be identity. Kansas City has its own unique identity, and the story may be about how the city's culture, traditions, and values contribute to that identity, and how the people of Kansas City identify with their city.
It could be a tale of adventure and discovery in a city known for its diamonds, maybe involving characters seeking precious gems or uncovering hidden secrets related to them.
A theme could be sacrifice. Pearl might have sacrificed a lot for Pink Diamond. In the fanfic, this could be explored in detail, like how she gave up her own freedom or desires to serve Pink Diamond. Also, the theme of identity could be present. Pearl's identity was so tied to Pink Diamond, and the fanfic could show how that affected her sense of self.
One possible theme could be self - discovery. The girl might discover different aspects of herself as she experiences the various colors and situations in the city.
One possible theme could be environmental change. If the octopus city is in an aquatic environment, changes in the water quality or temperature could be a major theme.
One possible theme could be adventure if Carolina was someone who explored new areas around the city or had some exciting escapades.