Lillie is also a main character. She has her own story arc, especially regarding her relationship with Pokemon and her growth from being initially afraid of them to becoming more confident. And her family's secrets might also play a role in the fanfic.
Ash is the central character for sure. Then there could be some new characters created specifically for the fanfiction. They might be the ones who instigate the betrayal. For example, a mysterious trainer who has a grudge against Ash. His friends in the Alola region play a big role too. They are the ones whose reactions to the so - called betrayal by Ash form a major part of the story. Pikachu, as Ash's most loyal pokemon, is also a key character as it has to deal with the situation where Ash is being betrayed.
Obviously, Ash is a main character. He is usually at the center of the story, going on his adventures in the Alola region.
Obviously, Greninja is one of the main characters as the title suggests its return. The trainer who was associated with Greninja before would also be a main character. They are likely to be central to the story's development.
Well, obviously Ash is the central character. Then there are the female characters from Pokemon Sun and Moon like Lillie, who is often a key part of the harem. She has a gentle and kind personality and her relationship with Ash is a major focus. Mallow is another one. Her love for cooking and her friendly nature towards Ash make her a popular character in these fanfictions. Also, Lana, with her unique bond with water - type Pokemon and her adventurous spirit, is usually involved.
Gladion is also quite popular. His cool and mysterious demeanor, along with his strong Pokemon battling skills, draw a lot of attention. Fanfic writers might write about his past, his relationship with his sister Lillie, or his battles against powerful opponents.
One common theme is Ash's growth as a trainer. In the Alola region of 'pokemon sun and moon', Ash faces new challenges and his experiences shape him into an even better trainer. Another theme is friendship. He forms new friendships with both people and Pokémon in Alola. For example, his relationship with his new Pokémon like Rowlet, Litten and Popplio is often explored in these fanfics.
One interesting storyline could be Ash's adventures in the Alola region with new Pokemon friends. He might face unique challenges and battles that are different from other regions. For example, dealing with the Totem Pokemon.
Obviously, Lillie is a main character. She is often the focus as the title suggests. In these fanfictions, she can be portrayed in various ways, from a shy and timid girl to a strong and fearless trainer.
The main character is the player - controlled trainer. There's also Professor Kukui who is important as he provides guidance. Lillie is another main character. She has her own story arc related to the mysterious Pokemon she's associated with. And then there's Hau, who is like a friendly rival to the player. These characters play crucial roles in driving the story forward in the Pokemon Sun and Moon anime game.
A fanfiction could focus on Ash Greninja's unique form and abilities. For example, it could tell a story where Ash has to rely on Greninja's special skills to overcome a powerful, mysterious Pokemon in the Alola region. This would show the significance of their partnership in the context of Pokemon Sun and Moon.