There's a chance that Ash will meet some Pokémon Rangers in Kalos. Rangers in Kalos have their own set of skills and responsibilities. Meeting them could lead to Ash getting involved in protecting Kalosian Pokémon from various threats. Also, he might run into some Kalosian Gym Leaders who are known for their strong Pokémon and strategic battles. Interacting with them would surely be an exciting part of his journey in the 'Ash travels Kalos after Alola fanfiction'.
Ash could meet new Kalosian trainers. These trainers might have Pokémon with different move sets and abilities compared to those in Alola. They could introduce Ash to new ways of training and battling. There could also be some important Pokémon Professors or researchers in Kalos that Ash would cross paths with, and they might offer him valuable insights about the Pokémon in Kalos or even about his own Pokémon.
He might meet Serena again. Since he has been to Alola and now travels to Kalos, their reunion could be an interesting plot point.
In this fanfiction, Ash might encounter new Pokémon species in Kalos that he didn't see in Alola. He could also meet different trainers with unique battling styles.
Well, one possible plot could be that in the Kalos region, Ash makes a new powerful rival. Haruka, being in Kalos for some reason, gets influenced by this rival's charm and power. In Alola, Ash discovers that Haruka has been secretly helping this rival against him, thus feeling betrayed. Maybe the rival promised Haruka something she couldn't resist, like a rare Pokémon or a chance to become a top - tier trainer in a different way.
The antagonist could be a powerful and devious Team Rocket member who has infiltrated the Kalos and Alola regions. This member could manipulate Haruka, perhaps by blackmailing her with something from her past in Kalos. In Alola, the Team Rocket member uses Haruka to get to Ash, making her betray Ash without really wanting to.
He could meet Serena, who might be his travel companion or a friendly rival. Also, Clemont and Bonnie are likely characters he'd encounter. They could help Ash with his journey in Kalos, like Clemont with his inventions and Bonnie with her cheerful nature.
He'll surely meet the Alola region's professors. Also, the local trial captains are very likely to cross paths with Ash. And of course, the regular Pokémon trainers in Alola.
Lillie is a likely character. She could befriend Ash and they might go on Pokémon adventures together. She has her own story and growth in the Alola region, and interacting with Ash could add more depth to both of their characters. Also, Ash might meet the Trial Captains like Mallow or Sophocles. They could challenge Ash in different ways and teach him about the island challenges.
He might meet new Pokémon trainers in Alola. Maybe some young kids who are just starting their own Pokémon journey.
One idea for a fanfiction could be that Ash travels to Kalos with his Infernape. There, Infernape discovers new moves or abilities inspired by the Kalos environment. It could be something related to the fairy - type energy prevalent in Kalos, which gives Infernape an edge in battles against certain opponents.
One popular aspect of Alola fanfiction with Ash could be his growth as a trainer. In the Alola region, Ash had unique experiences. Fanfiction might explore how he further developed his skills, formed new bonds with Pokemon, and interacted with the local culture. For example, his relationship with Pikachu might be delved into deeper, showing how they overcame new challenges together in the Alola setting.
Ash might meet some lone Pokémon trainers. These trainers could be on their own quests, similar to Ash's. They might have unique Pokémon or training methods that Ash can learn from.