Perhaps there are new characters created specifically for this fanfiction. For example, a young trainer who looks up to Ash's twin and wants to learn from them. This character could have their own set of Pokemon and bring new storylines. Another could be an older trainer who acts as a mentor to both Ash and his twin, teaching them special techniques and sharing wisdom about the Pokemon world.
There could be Brock. He might play an important role in guiding both Ash and his twin on their Pokemon journey. Another character could be Misty. She could be friends with both of them and offer her own unique perspective on Pokemon training.
They could start with some initial jealousy or competition. For example, if the twin is also a good trainer, they might compete for the attention of a famous Pokemon trainer. But as they face challenges together, like a powerful enemy team, they realize they are stronger together and start to support each other more.
Team Rocket might be main characters as well. They could be constantly trying to capture Ash or his Pokemon because of his special status. Their bumbling attempts to take advantage of Ash's link to Arceus could add a lot of comical and action - filled moments to the fanfiction. And of course, Arceus itself could be a major character, guiding Ash in some way or interacting with him directly.
Obviously, the Legendary Pokemon would be a main character. It could be a Pokemon like Mewtwo, who is often depicted as having a complex personality. It might start off as a mysterious and powerful entity that Ash has to befriend or battle against.
Since the term involves inappropriate content, we should focus on positive Pokémon fanfiction. For example, some fanfictions might be about Ash's adventures with his Pokémon, his journey to become a Pokémon master, and the friendships he forms along the way.
The OC themselves are often popular characters. Since they are original creations, they can have all sorts of unique personalities, abilities, and backstories. For example, an OC could be a shy but brilliant Pokemon trainer who gradually overcomes their insecurities with Ash's help.
Misty and Brock are also main characters in many of these fanfictions. After Ash's sacrifice, they might be the ones to comfort Pikachu and the other Pokémon. They could also take on Ash's unfinished tasks, like continuing to explore the Pokémon world, helping other trainers, and fighting against any emerging threats. Their friendship with Ash gives them the motivation to keep going in his absence.
Well, Ash is known for his impulsiveness and his heart - on - sleeve attitude. His twin brother could be the opposite, more calculating and perhaps a bit colder in his decision - making. Maybe he doesn't form such quick bonds with his Pokemon but instead has a more professional relationship based on training efficiency. Also, he might be more interested in the academic side of Pokemon, like studying their evolution patterns in depth, while Ash is more focused on the adventure and the battles.
There could be a new character, a rival to Ash's dad from his younger days when he was an active Pokemon trainer. This rival could reappear in the fanfiction, causing some trouble or adding some drama to the story.
One idea could be that Ash's twin has a different approach to catching Pokemon. For example, while Ash is more impulsive, the twin might be very strategic. Another could be that the twin has a special bond with a certain type of Pokemon that Ash doesn't. Maybe the twin has an easier time communicating with psychic - type Pokemon and uses this to their advantage in battles and adventures.
One popular character is Misty. She often appears in fanfiction and can have different roles. Sometimes she's a strong supporter of Ash in his Dex Holder adventures, and other times she might be on her own journey but still cross paths with Ash. Her feisty personality and love for water - type Pokemon make her an interesting addition to the stories.