The theme of self - discovery is also quite common. Ash may have realized his true feelings for Serena while on his travels, and Serena might have also discovered more about herself in his absence. Additionally, the theme of friendship is often intertwined. Their past friendship forms the basis for their new relationship when Ash returns.
Love and reunion are very common themes. The idea of Ash coming back to Serena after a long time apart, and them picking up where they left off or starting a new chapter in their relationship.
There's a fanfiction called 'Ash's Homecoming to Serena'. In this story, Ash returns to Serena with a newfound sense of purpose. The story focuses on how their relationship evolves from friendship to something more romantic. It has some great character development for both Ash and Serena.
One great 'Ash Return for Serena' fanfiction can be found on FanFiction.net. It often has detailed character development where Ash comes back into Serena's life in a very unexpected way, like during a Pokémon tournament she's participating in. The story then unfolds with their rekindled friendship and the potential for more.
One possibility could be that Ash comes back from war a changed man. He might have seen a lot of hardships and death, which makes him more mature. When he reunites with Serena, their relationship could be a bit strained at first. Maybe he has some PTSD and Serena has to help him through it, and in the process, their bond deepens more than ever.
Their relationship might start off with a lot of pent - up emotions. Ash could be a bit distant at first due to his war experiences, but Serena's love and care would gradually draw him out. Eventually, they would become closer as they share their feelings and experiences during the time they were apart.
In fanfiction, anything can happen. However, without specific details of the particular fanfic, it's hard to say for sure if Serena is pregnant. Some fanfictions might explore this plotline for the sake of drama or character development. It could add an interesting twist to the relationship between Ash, Serena and Lemon, but it also depends on the overall theme and direction the author wants to take the story.
They would probably be a bit shy at first. Ash being his usual energetic self but also respectful of Serena's space in the tent. Serena might be a bit nervous but also excited to be sharing such a close space with Ash.
A great idea could be a fanfiction about Ash and Serena traveling together to a new region to discover rare Pokémon. They could face challenges, make new friends, and help each other grow as trainers. This would focus on their relationship in the context of the Pokémon world and their shared goals.
For Ash, he could develop better communication skills. In the Kalos League, he often gets so focused on battles that he forgets to share his thoughts and feelings with Serena. By learning to communicate better, he can strengthen their relationship. For Serena, she could develop more self - confidence in her own Pokémon training skills. Maybe she starts out doubting herself but as the Kalos League progresses, she becomes more assertive and makes her own mark in the Pokémon training world.