It could be about the return of Pokemon Hunter J in a fan - created story. Maybe it involves her new hunts, encounters with different Pokemon, or her interactions with other characters from the Pokemon universe.
Obviously, Ash is one of the main characters. He is the Pokémon trainer on his journey to become a Pokémon Master. Hunter J is also a main character, a notorious Pokémon hunter who often causes trouble for Ash and his friends.
Obviously, Pokemon Hunter J would be one of the main characters. There might also be some Pokemon that play significant roles, either as her targets or as ones that oppose her.
A cool Pokemon Hunter J fanfic could focus on her facing off against a powerful trainer who is trying to stop her illegal activities. The battles between their Pokemon could be really intense, with the trainer using unique strategies. It could also show her slowly realizing that there might be more to life than just hunting Pokemon for profit.
One interesting plotline could be Ash and his friends trying to outwit Hunter J's devious plans to capture rare Pokémon. Maybe Hunter J sets a trap for Pikachu, and Ash has to use his wits and the bond with his Pokémon to rescue Pikachu.
One idea could be a story where Pokemon Hunter J has a change of heart. Maybe she encounters a particularly powerful and kind Pokemon that makes her question her ways. For example, she tries to capture a Latios, but it shows her kindness and she starts to hesitate.
One possible plot could be that Hunter J targets Ash for some unknown reason. Maybe she sees his unique bond with his Pokémon as a threat or something she wants to possess. Ash, being his usual brave self, has to outwit her while also protecting his Pokémon friends from her devious plans.
An old and wise Pokemon sage. This character could live in a hidden forest and have knowledge about ancient Pokemon powers. They could play a role in either helping Pokemon Hunter J find redemption or in protecting the Pokemon from her. For example, they could give J some cryptic advice that makes her think twice about her actions.
Create unique character relationships. For example, make her have a complex relationship with a Pokemon she catches but then starts to care for in a strange way. Also, add unexpected plot twists. Instead of the usual hunt - capture - sell cycle, throw in some elements that change her path completely.
I'm not sure specifically as 'fanfic' can cover a wide range of interpretations. It could potentially be a fan - created fictional story related to a character named Ash Hunter, but without more context it's hard to say more.