In such a fanfic, perhaps Ash and Paul were on a journey together in the Pokémon world. They might be part of a team for a big tournament. Then, one of them could make a deal with a rival group behind the other's back for personal gain, like getting access to a rare Pokémon. This would be the betrayal.
It's mainly Ash and Paul. But depending on the plot of the fanfic, there could be other trainers or characters involved. For instance, a new trainer who comes in between them and somehow instigates the betrayal. Or a Pokémon professor who might unknowingly play a part in the events leading to the betrayal.
The 'ash and paul betrayed fanfiction' could center around a variety of themes related to betrayal. It might be set in a world where their goals and ambitions clash, leading to one feeling betrayed by the other. For example, if they both have different ideas about how to train Pokémon or achieve victory in the Pokémon world. Paul might be very competitive and see Ash's more friendly approach as a betrayal of the 'true' way to be a Pokémon trainer. And Ash could feel betrayed if Paul were to, say, steal an opportunity from him in a crucial moment.
In this kind of 'ash and riolu betrayed fanfic', it might be that Ash and Riolu are in a Pokémon tournament. They meet a new trainer who seems friendly and offers to team up with them. However, during the tournament, this so - called friend betrays them by using underhanded tactics. This could include things like secretly weakening Riolu before a battle or spreading false rumors about Ash to other trainers. As a result, Ash and Riolu not only lose the tournament but also feel deeply hurt and betrayed.
It could be that Ash discovers some sort of secret about Harrison that he misinterprets. Instead of talking to Harrison about it, he takes actions that seem like a betrayal. For instance, Ash might tell others about this secret, thinking it's for the greater good, but it actually causes a lot of harm to Harrison.
Perhaps in the fanfic, a new and mysterious Pokémon arrives. This Pokémon is able to manipulate the thoughts of those around it. It makes Mewtwo believe that Ash is a threat to all Pokémon. So Mewtwo starts to act against Ash. Ash, on the other hand, is clueless as to why Mewtwo has suddenly turned on him. He has to dig deep into the secrets of this new Pokémon and find a way to reverse what it has done to Mewtwo.
You could start by looking on popular fanfiction websites like FanFiction.net or Archive of Our Own. Just use the search terms 'ash and paul betrayed' and see what comes up.
One possible plot could be that Ash and Misty share a kiss, which is witnessed by Paul. Paul, feeling out of place or perhaps jealous, decides to leave. After Paul leaves, Ash and Misty might have to deal with the aftermath of their kiss. They could face mixed reactions from their friends, and they themselves might be confused about their feelings towards each other. Maybe they start to explore a romantic relationship further.
Well, the Pokemon Ash vs Paul fanfic could be set in different regions. It could start with their first encounter, where there's an immediate clash of personalities. Ash's more friendly and open - minded approach contrasts with Paul's cold and calculating demeanor. As the story unfolds, their Pokemon battles become more than just about winning. They could be about proving a point, like Ash showing that kindness towards Pokemon can also lead to strength, and Paul realizing that there's more to Pokemon training than just power.
One idea could be that Ash is betrayed by his so - called friends in the Pokémon world. They might be jealous of his status as the Chosen One and team up against him. For example, Gary could spread false rumors about Ash, causing other trainers to doubt him.
I'm not entirely sure specifically about this 'evil ash betrayed fanfiction' as there could be many different interpretations. It might involve the character Evil Ash in a situation where he betrays someone or something within the context of the fan - created story.