Perhaps the fanfiction could be set in a post - apocalyptic Pokémon world where only Ash and Greninja remain as a team. They have to rebuild the Pokémon world while also dealing with rogue Pokémon and groups of humans who want to take over. Ash and Greninja would be the key to restoring balance and order, and their journey would be filled with many difficult decisions and epic battles.
One possible plot could be that Ash and Greninja start in a different region than the usual ones. They have to adapt to new Pokémon, new trainers, and new challenges. Along the way, they meet other trainers who are also starting with unique Pokémon, and they form a team to compete in a new kind of Pokémon league. Ash and Greninja would have to learn new battle strategies and overcome their differences to succeed.
Social media groups dedicated to Pokémon fanfiction can also be a great place to look. For example, on Facebook or Reddit, there are groups where fans post their works or recommend good fanfictions. So, search for relevant groups and look for the 'Ash starts with Greninja' fanfictions there.
Well, it could vary a great deal. In some 'ash greninja returns fanfiction', it might focus on Ash and Greninja reuniting after a long separation. Maybe Greninja has been in a far - off place training or on a mission, and now it comes back to Ash to help him in a big battle. They then team up again, with Greninja using its unique Water - Shuriken and other moves to take on powerful opponents.
One plot idea could be that the female Greninja has unique powers that only Ash can help her control. As they train together, they develop a deep bond that goes beyond a typical trainer - Pokémon relationship.
Perhaps it's a story where Ash and Froakie form an even deeper bond than in the original series. They might go on a quest to find a rare Pokemon that only Froakie can sense, and along the way, Ash learns more about Froakie's past and its potential. Froakie could also teach Ash some new strategies in battles that help him become a better trainer overall.
The plot might involve Ash starting his journey all over again, but this time with a Charizard as his very first Pokémon. Since Charizard is a powerful and somewhat stubborn Pokémon, Ash would have to learn how to handle it right from the start. He could face challenges like other trainers trying to steal Charizard because of its rarity. Ash would have to prove his worth as a trainer and his connection with Charizard to keep it by his side.
Well, it could be about Ash starting his journey with a Ralts. Maybe Ralts is a special one that has unique powers. Ash and Ralts could go through various gym battles together, with Ralts evolving at crucial moments to help Ash win. They might also face some tough opponents who are after Ralts' power.
The plot might involve Ash's Dratini evolving quickly due to their unique connection. It could also have elements of Ash trying to prove that Dratini can be a very powerful Pokémon from the start. He might enter it into Pokémon contests and battles, showing off its unique moves and abilities.
The fanfiction could revolve around Ash and Riolu's bond. Since Riolu can sense auras, it might be able to sense Ash's strong will and determination. They could go on an adventure to discover more about Riolu's species and its hidden powers. Along the way, they meet other trainers and Pokémon, and Riolu grows stronger with Ash's guidance.
Well, the plot might be that Ash stumbles upon a lost Togepi. Since Ash has a kind heart, he takes it under his wing. They then embark on a journey where Togepi starts to show some extraordinary powers that no one has ever seen before. This attracts the attention of Team Rocket who try to capture it. Ash and his friends have to come up with clever plans to outwit Team Rocket every time they make an attempt.
One possible plot could be that Ash, instead of starting with Pikachu in the Alola region, starts with Litten. Litten could be a difficult Pokémon to train at first, but Ash's determination helps him bond with it. They could go on adventures in Alola, facing Team Skull together and Litten evolving as they overcome various challenges.