Ash could develop his ability to understand different Pokemon cultures better. Cynthia, being from a different region, has a lot of knowledge about various Pokemon traditions. Ash could learn from her and in turn, teach her about his own experiences. This exchange could make Ash more worldly and Cynthia more in touch with the broader Pokemon community. In terms of their relationship, they could start to rely on each other more, which would be a big step for both of them character - wise.
It could be a jealous fellow trainer. There are always those in the Pokémon world who envy the skills and achievements of others. This trainer might see Ash and Cynthia as obstacles to their own glory and decide to betray them to get ahead.
I'm not sure specifically as I haven't read this fanfic. But it might be about Ash being taught by Cynthia in the context of the Pokémon world. Maybe she's teaching him battle strategies or some special Pokémon knowledge.
Romance is also quite common. Fans like to imagine a relationship between Ash and Cynthia, so many fics will explore their feelings for each other, how they meet cute, and how their relationship develops over time. Another theme could be mentorship. Cynthia being an experienced trainer might mentor Ash in some aspects of Pokémon training, like teaching him new battle strategies or how to better understand certain Pokémon types.
They would become more united and responsible. Their relationship would shift from just being friends or fellow trainers to co - parents. They would need to communicate more about the baby's needs, like what kind of Pokemon - related education to give the baby.
In the fanfiction, the baby might inherit Ash's adventurous spirit and Cynthia's strategic mind. So when it comes to Pokemon exploration, it would be fearless in going to new places. But when it's time for battles, it would carefully plan out every move. It could also befriend Pokemon in the wild very easily, much like Ash, and have a deep understanding of Pokemon types like Cynthia.
One common theme could be adventure. Since Ash is known for his Pokémon - collecting adventures and Cynthia is a strong trainer, they might embark on new quests together in fanfiction. Another theme could be love and relationship development as fans explore their potential romantic connection.
Well, it could be that Ash, perhaps after some difficult times in his own journey, finds a new family with Cynthia. Maybe she sees his potential and decides to take him under her wing, guiding him in his Pokémon training in ways he hadn't experienced before.
One common theme is friendship development. As they travel together, Ash and Cynthia grow closer as friends. Another theme is Pokémon discovery. They often find new and rare Pokémon during their travels.