One possible fanfiction could be about Ash's adventures in Hoenn during the month of May. Maybe he discovers a new Pokémon species that is only active during this time of the year. He could be traveling with his usual companions and facing challenges specific to the Hoenn region.
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.
Often, these fanfictions will take the characters out of their normal settings. For example, they might end up in a different time period or a strange new land. This allows for a lot of creativity in the storylines. And the character development of May and Ash is usually a big part of it, showing how they grow and change throughout the story.
Yes, there might be. Fanfiction covers a wide range of scenarios and relationships, so it's possible that someone has written a story where May cheats on Ash. You can try searching on popular fanfiction websites.
A possible fanfiction plot could be that Ash, Serena, and May are invited to a mysterious island full of unknown Pokemon. They have to work together to survive and discover the secrets of the island. Ash's leadership, Serena's ability to communicate with Pokemon, and May's quick decision - making skills would be crucial.
One way is to focus on their friendship. For example, write about how they support each other during Pokémon battles. They can exchange tips on training Pokémon or strategies for winning competitions.
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.
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.
Definitely their Pokémon friends. Pikachu, of course, would be there. May's Blaziken and Ash's Greninja would also be among the guests. Their human friends like Brock, Misty, and Dawn would surely come. And perhaps some of the Gym Leaders they've met during their travels would also attend, like Roxanne from Rustboro City.
Sure. There are fanfictions where they are just good friends and they help each other out in Pokemon battles or in exploring new regions. Their relationship can be shown as a strong bond based on mutual respect and support without any romantic or inappropriate content.