One common theme is adventure. Given their backgrounds in the Narnia stories, fanfictions often send them on new quests. For example, they might explore uncharted parts of Narnia or other magical realms.
Fanfiction can provide a sense of continuation. Since their own story might have ended, fanfiction gives them the opportunity to be part of new tales, with new challenges and emotions. It also lets them explore aspects that weren't fully developed in the original story, like their deeper friendship or potential romantic feelings.
Romance is also a big theme. Writers like to explore the potential relationship between Caspian and Lucy. They might write about how their feelings for each other develop over time, from initial admiration to deep love. It could involve cute moments like sharing a secret in a hidden garden in Narnia.
A common theme is the 'forbidden love' aspect. Since they come from different worlds in the original stories, fanfictions often play on the idea that their love is something that goes against the norm or is difficult to pursue. Another theme is the 'growth through love'. Their relationship helps them both grow as individuals, with Lucy becoming more confident and Caspian becoming more open - hearted.
One common theme is adventure. Since they are characters from Narnia, the stories might involve them going on adventures while taking care of a baby. Maybe they are on a quest and have to protect the baby at the same time.
One common theme is the exploration of different cultures. Since Lucy is from one part of Narnia and Caspian has his Telmarine roots, their marriage often involves melding these two different ways of life.
In general, the Chronicles of Narnia has a wide range of fanfiction themes, from exploring different character relationships to creating new adventures. But the idea of Lucy being pregnant is not a typical or common one. The series is set in a magical world full of talking animals, mythical creatures, and epic battles. While fanfiction can deviate from the original, this particular theme seems to go against the more innocent and adventure - based nature of the source material. So, it's not that common in Narnia fanfiction.
One possible plot could be that they face challenges in Narnia while Susan is pregnant. Maybe there are threats to the kingdom that they have to deal with together, all while preparing for the arrival of their child. Caspian might be extra protective of Susan, and they could rely on the help of their friends in Narnia.
Susan could develop into a more nurturing figure. Since she's pregnant, she might become more in tune with the needs of others in Narnia, not just her own family. Caspian, on the other hand, might grow in his sense of responsibility. He now has a family to protect, so he may make different decisions regarding the kingdom.