The Pokémon in Ash's harem would be a major part of the characters. This could include Pokémon like Bulbasaur, Charmander, and Squirtle. Each of them has its own personality and abilities, and in the fanfiction, they interact with Ash in different ways, whether it's during battles or in more relaxed, everyday situations.
Ash is of course a very common character as he is the central figure. Pikachu is also often included as it is Ash's most well - known Pokémon. Other characters like Misty and Brock might also make appearances as they are Ash's friends and travel companions in the original Pokémon series.
One common theme is adventure. Ash and the Pokemon mothers often go on adventures together. Another is relationship building, exploring how Ash interacts with all the different Pokemon mothers in this harem - like setting.
Ash is obviously one of the main characters. He is at the center of the harem concept. Then there would likely be a group of human characters who are part of his harem, though their specific identities can vary greatly depending on the fanfiction.
The exploration of the Pokemon world is another theme. These fanfictions usually don't just focus on the harem aspect but also on Ash's adventures in different regions, his encounters with new Pokemon species, and his participation in Pokemon contests or battles. This combination of harem, romance, and Pokemon - related adventures makes these fanfictions appealing to many readers.
One common theme is loyalty. The Pokemon in the harem are often extremely loyal to Ash, following him everywhere and being willing to protect him at all costs. Another theme is friendship. The relationships are based on deep friendship that has elements of a harem, like the Pokemon all wanting to be close to Ash. Growth is also a theme. Ash may grow as a trainer as a result of his interactions with his Pokemon harem.
One common theme is friendship. Since Ash is at the center, his relationships with the pokemon mothers in the harem often involve elements of friendship that develop into something more. Another theme could be adventure. Ash's journey in the pokemon world is filled with adventures, and this is often incorporated into these fanfictions as well.
Misty is often in Ash's harem in fanfictions. She has been with Ash since the beginning of his journey and their relationship has a long history. Another common one is Serena. She has strong feelings for Ash and her character development is closely tied to him.
A common theme in such fanfictions could be Ash's adventures in Alola while building relationships with different characters. Maybe he forms special bonds with his Pokémon and the people around him in a more romantic or friendship - deepening way.
Ash is obviously the central character. Then there are the female characters from the Alola region that often form his harem. Lillie is a very common one. She has a gentle and kind personality and her relationship with Ash can be explored in many ways in the fanfictions. Another is Mallow. Her love for cooking and her energetic nature make her an interesting character to include in the harem. And there's also Lana, with her love for water - type Pokemon.
One common theme is trust and its breakdown. Since Ash is betrayed, it focuses on how trust is lost among the characters in the harem.
One common theme is the exploration of different relationships. Since it's a harem concept, Ash has multiple Pokemon around him with various types of relationships. Another theme is adventure. The harem often goes on adventures together. And of course, there's the theme of loyalty among the Pokemon in the harem towards Ash.