Perhaps Ash, as a Victini, would attract a lot of attention from other Pokémon and trainers. Some might see him as a symbol of hope and victory, while others could be jealous or even try to capture him for his powers. His friends, like Pikachu, might be initially confused but would eventually learn to accept this new form of Ash and help him navigate the challenges that come with being a Victini.
Obviously, Ash would be one of the main characters, since he's the one turning into Victini. Pikachu would also be important as Ash's most loyal Pokémon. And Victini itself could be a key character, either as a part of Ash now or as an entity that helps Ash understand his new form.
One way is through shared goals. For example, if there is a powerful and evil Pokemon causing trouble in the region. Ash wants to stop it for the sake of the Pokemon and people, and Victini wants to stop it because it threatens the balance of the Pokemon world. As they work towards this goal, they learn about each other's strengths and weaknesses. Ash might learn that Victini is afraid of certain types of attacks, and he protects it. In return, Victini uses its victory power to give Ash's Pokemon an advantage in battles. This mutual reliance and protection deepens their relationship.
One idea could be that Ash and Victini team up to save a special forest that is being threatened by a dark - type Pokemon. Victini uses its power of victory to boost Ash's Pokemon in battles against the dark - type's minions. Another plot could be Victini getting lost and Ash helping it find its way back home while facing various challenges together. They might also encounter a rare and powerful Pokemon that only Victini can communicate with, and they have to figure out how to work with it to solve a mystery in the Pokemon world.
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.
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.
Well, if Ash turns into a Pikachu in a fanfiction, it would be quite a transformation. Firstly, his communication with Pikachu would become more of an internal dialogue. And he'd have to get used to moving around on all fours and using Pikachu - like movements. His battles would be completely different too. He'd be relying on Pikachu's natural skills rather than his own battle strategies as a human trainer.
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.
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.
One common theme is Victini's power. Since Victini is known for its ability to bring victory, many fanfictions explore how it uses this power in different situations, like in battles or helping trainers overcome difficulties.