Well, sometimes the antagonist can be an internal struggle within Ash or May themselves. For example, Ash's over - ambition to become the best Pokémon trainer might lead him to make choices that seem like a betrayal to May. His single - minded focus on winning battles and collecting badges could make him neglect May's feelings. In this case, Ash's own ambition is acting as the antagonist in the story. Similarly, May's insecurities could make her misinterpret Ash's actions as betrayal, and her insecurities then become the antagonist in the relationship.
It could be a Team Plasma - like organization that is causing trouble in Unova. They might be trying to steal Pokémon or disrupt the balance in the region, and Ash and May have to stop them.
The main characters are Ash and May, of course. Ash is a well - known Pokemon trainer with a passion for catching and training different Pokemon. May is also a trainer who has her own goals and journey in the Pokemon world. In this fanfiction, their relationship takes a turn due to the betrayal aspect.
It could be a rival trainer. Rival trainers are often very competitive in the Pokémon world. Maybe this rival is jealous of Ash and May's progress and decides to betray them to slow them down. They might spread false rumors about Ash and May, causing other trainers to be distrustful of them.
One type of antagonist could be a corrupt Pokemon League official. In the fanfic, this official might bribe Ash to do something unethical, like throwing a battle against Iris. When Iris finds out, she'll feel betrayed. Another likely antagonist is a Pokemon hunter. If the hunter captures a Pokemon that Ash and Iris both care about, and Ash, in an attempt to rescue it, makes a deal with the hunter that seems to go against Iris's values, she'll feel betrayed. And sometimes, it could be a self - centered Pokemon trainer who wants to be the only star. They might set up Ash and Iris to fight each other and make it look like one has betrayed the other.
Ash could get angry. He has a strong sense of justice, and he might feel that May has violated their friendship. He could challenge her, not in a violent way, but more in a way to get an explanation and to try to make her see the error of her ways. He would likely be determined to show her that what she did was wrong.
One possible main antagonist could be a powerful and arrogant trainer who wants to prove that he is better than Ash and Nora. He might try to steal their Pokemon or sabotage their battles.
Team Rocket could be the main antagonists. They're always causing trouble for Ash and his friends, and they'd surely be after Ash and Leaf on their journey too, trying to steal their Pokémon.
Well, sometimes it could be a new team of villains. Maybe a group of poachers who are after rare Pokémon in the Libre fanfiction setting. They would directly oppose Ash and Pikachu as they try to protect the Pokémon.
Perhaps May betrays Ash because she's influenced by a new group of trainers. They might convince her that Ash's way of training Pokémon is wrong or that he's holding her back from achieving greater things. So, she sides with them against Ash. This would show how easily friendships can be tested in the competitive world of Pokémon training.
Ash would initially be heartbroken. He has shared so many adventures with May, and this betrayal would shatter his trust. He might go off on his own for a while to think things through. When he comes back, he could be more determined than ever to prove himself without May. He might also be a bit more cautious when it comes to making new friends. His Pokémon would sense his distress and try to comfort him, but it would take a long time for him to fully get over May's betrayal.