Perhaps the fanfiction could revolve around a time when Serena's mom was also a young trainer. Ash somehow travels back in time and meets her. They team up for a Pokemon adventure. During this, Serena's mom might see some of Ash's qualities that remind her of Serena in the future. This experience could then have an impact on how Serena's mom raises Serena later on, creating a sort of circular connection in the story.
One possible plot could be that Serena's mom discovers Ash's true potential as a Pokemon trainer and decides to help him in his journey. Maybe she has some old Pokemon training techniques that she imparts to Ash, which helps him win a big tournament.
It could be a powerful Pokemon trainer who is jealous of Ash's connection with Serena's mom. This trainer might try to disrupt their relationship and stop Ash from getting any help or knowledge from her.
Maybe in this fanfiction, Ash has been planning the proposal for a long time. He enlists the help of all their Pokémon friends. Pikachu holds the ring in its tiny paws. Ash takes Serena to a place that holds special memories for them, like the place where they first met. He then gives a heartfelt speech about their journey together and how he wants to continue it as her partner forever before popping the question.
One idea could be that Ash and Serena meet again after years apart. Ash has become a Pokemon Master and Serena has achieved great success as a Pokemon Performer. They decide to travel together again, this time not just for their own goals but to explore new regions and discover new Pokemon species together. Along the way, they face challenges from Team Rocket who have a new evil plan. Their relationship deepens as they support each other through these difficulties.
Well, it could be that Ash finally realizes his deep feelings for Serena during a grand Pokemon event. Maybe they are in a beautiful, flower - filled meadow near a Pokemon Center, and Ash gets down on one knee with a Pokemon - themed ring, perhaps made from a shiny Pokemon scale or something unique.
Well, one possibility is that Ash finally realizes his true feelings for Serena during an adventure. Maybe they are facing a dangerous situation, and in that moment of intensity, Ash blurts out his confession. It could be a really heart - warming moment for fans who ship them.
Well, it could be about Ash and Serena going to a Pokémon-themed park on their date. They might encounter some rare Pokémon there and have an adventure together while also getting to know each other better on a more personal level.
Well, it could start with Ash finally realizing his true feelings for Serena. They might have a small, intimate wedding in a Pokémon - filled meadow. All their Pokémon friends would be there, helping to decorate with flowers and berries. Pikachu could be the ring - bearer. And Serena would look stunning in a white dress inspired by Pokémon fashion.
The plot could involve Ash and Serena finding a baby Pokémon that is in a situation similar to being an orphan. Since they have such a strong bond, they decide to take it in and raise it as their own. They then have to learn how to take care of this special Pokémon baby, which includes finding the right food, a safe place to live, and teaching it important skills. Their friends from their Pokémon adventures might also get involved, some being supportive and others being a bit skeptical at first.
It could be that Ash crossdresses accidentally. Maybe they stumble upon a magical or mysterious place where some strange power causes Ash to transform into a female - like appearance. Serena then has to deal with this new - looking Ash. They have to find a way to reverse the effect while also facing any challenges that come their way during this time, like dealing with Pokemon battles or other trainers who react differently to this new - looking Ash.
One possible plot could be that their daughter discovers a hidden power within herself. Maybe she has an affinity for a type of Pokémon that neither Ash nor Serena had a special connection with. For example, she might be able to communicate with Ghost - type Pokémon in a unique way. This could lead her on an adventure to figure out where this power came from and what she's supposed to do with it.