The story could focus on Ash exploring other aspects of the Pokémon world, like Pokémon research or Pokémon care. He might use his experience as a trainer to help those in need in different ways.
Well, when Ash stops being a Pokémon trainer in fanfiction, the story could take many turns. It could show Ash trying to find a new identity in the Pokémon world. Maybe he starts a business related to Pokémon products. The story could also explore how the Pokémon training community reacts to his departure. Some might be disappointed, while others might understand his decision. His former rivals could also change their attitude towards him, from seeing him as a competitor to respecting him as a person who has made a big change in his life.
Some of his Pokémon might be very confused and sad. Pokémon like Pikachu, who has been with Ash for a long time, would probably miss the adventures and battles they had together. Pikachu might try to cheer Ash up and convince him to change his mind.
One reason could be that Ash has achieved all his major goals as a Pokémon trainer. He might have won all the important championships and feels there's nothing more to prove in that area. Another reason could be that he has had some kind of traumatic experience related to Pokémon training, like losing a very dear Pokémon in a battle that makes him not want to continue. Maybe he has also found a new passion, such as Pokémon research. He could have met some inspiring Pokémon researchers and decided to shift his focus from training Pokémon to studying them.
One great fanfiction about Ash as a legendary Pokémon trainer could involve him traveling to a new, mysterious region filled with rare and powerful Pokémon. He might start with his Pikachu, of course, and gradually build a team of Pokémon that are not only strong but also have unique abilities.
One reason could be that he gets tired of the constant traveling and battles. It's a very physically and mentally exhausting lifestyle. Another might be that he experiences a major loss, like losing his beloved Pokémon, which makes him lose his passion for training. Or perhaps he discovers a new interest that he finds more fulfilling than Pokémon training.
The story could develop with Hermione trying to figure out what went wrong. She might start investigating, talking to other friends they have in common to see if they know anything. Meanwhile, Harry could start making new friends who are more in line with his new mindset. But he might start to realize that he misses Hermione's unique qualities.
At first, his Pokémon would be startled. They've always known Ash as a human. But then, they would start to adapt. Some Pokémon, like Squirtle, might try to play with Ash in his new form, thinking it's a new kind of game. However, his more loyal Pokémon, like Greninja, would be determined to find a way to turn Ash back. Greninja might use its special bond with Ash to try and communicate with him on a deeper level in this new form, to understand what happened and how to reverse it.
The story would likely become more about Ash's internal struggle. As a Pokémon, he'd view the world from a different perspective. His goals might shift from winning badges to something more related to Pokémon survival or acceptance. For instance, he may strive to prove that Pokémon with human - like intelligence deserve better treatment.
Some fanfictions focus on Ash's relationships with other trainers in the context of being a legendary trainer. He could form alliances with other powerful trainers, and together they face challenges like tournaments where the stakes are not just victory, but also the fate of the Pokémon world.
Going to the Pokémon trainer school is a big step for Ash. He'll be surrounded by like - minded people who are all passionate about Pokémon. This can inspire him to come up with new strategies for battles. He may also learn about the history of Pokémon training, which can give him a deeper understanding of the whole Pokémon world. Moreover, the school may offer opportunities for him to trade Pokémon with other students, allowing him to diversify his Pokémon team and gain new skills and abilities.
If Ash was secretly a Pokémon, trainers might view Pokémon in a whole new light. They would see that Pokémon could be more like them, with complex emotions and motives. Also, Ash's relationships with other Pokémon and trainers would be re - evaluated. His Pokémon friends might see him as an equal rather than just a trainer.