His relationship with Pikachu would be very different. They'd be more like equals now. Pikachu might even feel the need to protect Ash more. With his other Pokemon, they might be confused at first but then develop a stronger bond as they realize it's still Ash inside.
The story would become more about Ash adapting to his new form. He'd have to learn how to move, eat, and sleep like a Pokemon.
If Ash becomes a female in the fanfic, his relationships with his Pokemon friends would also be different. His Pokemon might sense the change and some could be more affectionate, while others might be a bit confused at first. Regarding his human friends, his relationship with Gary would take an interesting turn. Gary might be more intrigued by this new Ash and could either be more competitive or try to help her adjust. And when it comes to Professor Oak, he might be more fatherly or have different expectations of Ash now that she is female, perhaps expecting her to focus on different aspects of Pokemon research or training.
His Pokémon might be really confused at first. They're used to Ash as a human, so seeing him as a Pikachu would be quite a shock. But some of them, like Pikachu himself, might feel a closer bond since Ash is now in a similar form.
Ash's relationships with his Pokemon would likely change significantly. Kalos has its own unique ecosystem and Pokemon culture. His Pokemon would be exposed to new stimuli and experiences. For instance, the Kalosian food for Pokemon might be different, and Ash would need to figure out how his Pokemon like it. Also, new training methods in Kalos could either strengthen or test the relationships. Ash would need to be more attuned to his Pokemon's needs and feelings in this new environment.
Well, if Ash were to turn into Mew in a fanfiction, it would be quite a wild turn of events. Mew is known for its ability to transform and its vast psychic capabilities. Ash, with his new form, could potentially travel to different dimensions that were previously inaccessible. He could also communicate with Pokémon in a whole new way, using Mew's psychic powers to understand their deepest thoughts and feelings.
In fanfiction where Ash turns into a girl, it could lead to some interesting plot twists. Maybe his relationships with his Pokémon would change in unique ways. For example, some Pokémon might be more protective of him now that he's a girl. Also, his interactions with other trainers, like Misty and Brock, would be different. They might treat him with more chivalry or have different emotional responses to his new form.
Another possibility is Ash becoming Lugia. Lugia is known as the guardian of the seas. As Lugia, Ash could explore the deep oceans, discover new species of Pokemon, and safeguard the marine ecosystem. He could use his psychic and flying abilities to interact with both water - and flying - type Pokemon, bringing a new era of harmony between different Pokemon types.
His Pokémon might become closer as they face new and unfamiliar situations together in Alola. They would rely on each other more for support and protection.
In this fanfiction, if Ash turns into a pokemon, perhaps he becomes a Charmander. He could struggle with being in a different form. He might have to adapt to the life of a fire - type pokemon, facing challenges like being weak against water - type attacks and trying to find a way to change back while still having adventures with his friends, who now have to protect him in a different way.
At first, his Pokémon would be shocked. They've known Ash as a human trainer, and now he's this powerful psychic Pokémon. The more aggressive Pokémon in his team might see him as a threat to their position in the group. But the loyal ones, like Bulbasaur, would try to understand what happened. Ash, in his new Mewtwo form, would have to use his psychic abilities to communicate in different ways. He might be able to understand his Pokémon's thoughts more deeply, which could either strengthen or strain their relationships depending on how they all adjust.