Perhaps the twin is more interested in the scientific aspects of Pokemon. They might study the evolution patterns in a different way than the professors in the Pokemon world. Ash and his twin could then combine their knowledge, Ash's practical battle skills and the twin's scientific knowledge, to solve some mysteries about rare Pokemon.
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.
In a fanfiction plot, perhaps Ash and Richie are twins who were sent to different regions by their parents for some mysterious reason. As they grow up, they both become excellent Pokemon trainers. When they finally meet, they initially compete against each other. But then they realize that together they can achieve more. They might then explore ancient Pokemon ruins together, where they discover secrets about their family and the origin of some powerful Pokemon.
One idea could be that Ash's twin brother was separated at birth and raised in a different region. He might have a different approach to training Pokemon, perhaps focusing more on strategy than Ash's instinctive style. Another plot could involve the twin having a special bond with a rare or legendary Pokemon from the start, which sets him on a unique journey.
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.
One idea could be a story where a Pokemon accidentally loses its covering (like a Pikachu losing its fur due to a magical mishap) and is embarrassed about it. It could then go on a journey to find a way to restore its normal appearance.
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.
A great non - adult Hypno - related Pokemon fanfiction idea is to have Hypno be a mentor to a young, newly - evolved Pokemon. Hypno could teach it how to better control its new powers. For instance, if a Psyduck has just evolved into Golduck, Hypno can use its own psychic experience to show Golduck how to focus its mental energy. Or, Hypno could be involved in a story where it teams up with other Psychic - type Pokemon to protect a special place in the Pokemon world that is rich in psychic energy from poachers or other threats. Also, a story where Hypno uses its powers to unlock the hidden potential of a seemingly ordinary Pokemon, like a Rattata, could be really interesting.
Perhaps in the fanfiction, Cynthia could be mentoring Ash in some advanced Pokemon battling techniques. Ash, being eager to learn, follows her guidance and in the process, they develop a deeper bond. This could lead to them exploring new regions together in search of rare Pokemon for training.
One interesting plot idea could be that Ash and Sakura team up to enter a special Pokemon tournament that features rare and powerful Pokemon. They have to train hard together, with Sakura's knowledge of different Pokemon types and Ash's battle experience combining to give them an edge.
Perhaps Daisy discovers a new type of Pokemon that is extremely rare, and she enlists Ash's help to study it. Along the way, they face off against a group who wants to capture the Pokemon for its power. This could lead to many adventures and battles for them.