One possible fanfic could be about Ash's journey to become the Kalos champion. It might start with his arrival in Kalos, full of excitement and determination. He meets new Pokémon and friends along the way. His battles are intense, with him using unique strategies to defeat his opponents and gradually climb the ranks to the championship.
A great 'Ash becomes Kalos Champion' fanfiction would have a strong sense of progression. Ash should start at a certain level and gradually become more powerful as he overcomes various obstacles in Kalos. The fanfiction could also explore the backstories of his Pokémon in more detail, like how they came to be with Ash and what their own goals are. Additionally, the way Ash interacts with the local Pokémon and trainers in Kalos can add depth and authenticity to the story.
One likely betrayer could be Serena. Maybe she has some hidden motives that are revealed when Ash becomes champion. For example, she might be jealous of his success and the attention he gets as champion, and so she betrays him.
One possible plot could be that Ash's so - called friends in the Kalos region turn on him out of jealousy. Maybe they can't handle the fact that he has become the champion. They start spreading false rumors about him, which makes the public turn against Ash. This betrayal could lead Ash to question his own journey and the relationships he has formed.
One key element is the battles. Since it's about Ash as the Kalos champion, the battles need to be exciting and well - described. His Pokémon's moves, the strategies he uses, and the reactions of the opponents are all important. Another element is the relationships. His friendship with his Pokémon, his human friends in Kalos like Serena, Clemont, and Bonnie. And also his relationship with the Kalos region itself, how he explores and falls in love with the place.
A great plot twist could be that the Kalos champion turns out to be an impostor. Ash discovers this during his journey towards the championship. This would mean that all the battles leading up to the championship were based on a false premise. Ash then has to not only expose the impostor but also face the real champion in a series of unforeseen challenges. Also, there could be a twist where Ash's Pikachu loses its ability to use electricity temporarily, forcing Ash to rely on his other Pokémon in new and creative ways.
Overcoming challenges is also a major theme. There are always tough opponents and difficult situations in these fics. Ash has to find ways to defeat powerful trainers and deal with various problems that come his way. This shows his perseverance and determination to achieve the champion status.
His team might gain some new Kalos Pokémon. For instance, he could catch a Fennekin which later evolves into Delphox. This new addition would bring in new moves and abilities. Maybe he would also trade one of his existing Pokémon for a unique Kalos Pokémon that has a special advantage in the Kalos battles.
One idea could be Ash facing off against old rivals who are jealous of his new Kalos champion status. They challenge him in unique battles that test his skills in new ways.
There's a great 'ash becomes champion fanfic' called 'Ash's Champion Journey'. In this fic, Ash not only battles strong opponents but also overcomes his own self - doubts. It really shows his growth as a trainer. The writer does an amazing job of portraying Ash's determination and the relationships he has with his Pokémon.