The plot could revolve around Ash's initial confusion and conflict. He might join Team Rocket thinking he can change them, but soon realizes it's not that easy. His loyalty to his old friends would be tested as he gets drawn deeper into Team Rocket's plans.
Well, if Ash joined Team Rocket, he'd probably bring a whole new dynamic. His skills as a trainer could be used in unexpected ways. Maybe he'd try to reform Team Rocket from the inside, using his kind heart and love for Pokémon to change their ways. He could also introduce new strategies for capturing Pokémon that are more ethical than Team Rocket's usual methods.
If Ash joined Team Rocket in a fan fiction, his Pokémon might be really confused at first. Pikachu, for example, is used to Ash being a good guy. But over time, they could adapt. Ash could start to see the Pokémon world from a different perspective, like how Team Rocket views Pokémon as a means to gain power and wealth. However, deep down, Ash's kind heart might still shine through and he could end up changing Team Rocket from the inside instead of fully becoming a bad guy.
The Pokémon might initially think it's some sort of joke or mistake. But as time goes on, if Ash seems serious about being with Team Rocket, they could become divided. Some of the more headstrong Pokémon might leave Ash, while others might stay with him out of loyalty but still be unhappy about the situation. They would be constantly trying to nudge Ash back to his old ways of being a good Pokémon trainer.
Yes, in some Team Rocket fanfictions, Ash can be depicted in various ways that might involve him having some sort of connection to Pokémon in a different light. Maybe he could be experimented on by Team Rocket to gain Pokémon - like abilities, or be transformed into a Pokémon - like being in a very creative and out - of - the - box fanfiction concept.
If Team Rocket turns Ash into a Pokemon, it could lead to a really interesting story. Ash would have to experience the world from a Pokemon's perspective. He'd understand their struggles, like being caught and trained. This could also be a way for him to better understand his own Pokemon and their bond with him. And it would be a wild adventure as he tries to find a way to turn back to his human form.
Another plotline might involve Ash teaming up with some of the Team Rocket members, perhaps reluctantly at first. They could be forced to work together due to a common threat to both the good guys and the bad guys in the Pokemon universe. This would lead to some interesting character developments for Ash as he has to deal with the not - so - good nature of Team Rocket.
In a fanfiction where Ash joins Team Rocket, it could lead to some really interesting storylines. Ash has a lot of knowledge about Pokémon training that Team Rocket lacks. He could potentially teach them new techniques, but at the same time, his moral compass would be constantly at odds with their devious ways. Maybe he joins them because he's somehow tricked or he has his own secret plan to take them down from the inside. It would be a great opportunity to explore different aspects of his character and how he adapts to this new situation.
It really depends on the specific fanfic. Some might depict Team Rocket having a grudging respect or even a soft spot for Ash, while others might keep their adversarial relationship intact.