Their relationship develops as they face challenges together. In Kanto, every new Pokemon they encounter, every Gym battle Ash participates in, Serena is there. She cheers him on, and through this shared experience, they grow closer. For example, when Ash loses a battle, Serena is there to comfort him, and this makes their bond stronger.
One interesting plotline could be Ash encountering a rare and powerful Pokémon that isn't part of the original Kanto Pokédex. For example, a shiny Mewtwo that he has to befriend instead of battle. Another could be Ash getting lost in an uncharted part of Kanto and having to rely on his Pokémon's unique skills to find his way out, like Pikachu using its electricity to create a signal. Also, a plotline where Ash teams up with a group of Pokémon trainers who have different goals but they all learn from each other during their journey.
Ash and Pikachu are the top ones. But in addition to them, Nurse Joy is quite popular in some fanfictions. She can be more than just the healer of Pokémon, like having a secret past or special powers. Officer Jenny is also sometimes a key character. Her role in maintaining law and order in Kanto can be expanded in fanfiction. And then there are the Gym Leaders of Kanto. Each Gym Leader has their own fan following, and they can be written in many different ways in fanfiction to interact with Ash and his journey.
In the fanfiction, Ash might encounter unique Pokemon not typically found in the main Kanto storyline. He could also form different relationships with his companions. Maybe he faces a new and powerful villain that isn't in the original.
A common theme is friendship. Ash forms many bonds with his Pokémon and fellow trainers during his Kanto journey, and fanfics often explore these relationships further. Another theme is growth. Fans like to write about how Ash develops as a trainer in Kanto, learning new battle strategies and becoming more confident.
A plot could involve Ash finding a time - traveling device during his Kanto journey. He accidentally travels back in time and meets a younger version of Professor Oak. Together, they solve a mystery that has been affecting the Pokemon in Kanto for generations.
Another important moment could be their visit to the Pewter City Gym. Ash is eager to battle Brock, and Serena might be nervous for him. Ash's battle strategy and how Serena supports him during the fight could be a crucial part of the story. Maybe Serena gives Ash some advice based on her observations, which helps him win the battle.
He might meet a mysterious old trainer who imparts some unique wisdom. There could also be a young and talented trainer who becomes his rival or friend.
Ash's character in the Kanto fanfiction with Lillie might develop in terms of his leadership skills. He often takes the lead in their adventures, making decisions that affect both of them and the Pokemon they encounter. Lillie's development is more about self - discovery. In Kanto, she discovers her own strengths and weaknesses. She realizes that she has a natural ability to calm down agitated Pokemon, which she uses to help Ash during battles. Their time in Kanto is filled with challenges that shape their characters in different but complementary ways.