There could be unfinished business between them. They might have a shared goal that they haven't achieved yet. Greninja's return to Ash in the fanfiction could be to finally complete that goal, whether it's winning a particular Pokemon tournament or saving a certain place from destruction.
One popular Ash and Ash - Greninja fanfiction could be those that focus on their adventures in a new, unexplored region. In these stories, they might face unique and powerful Pokémon, strengthening their bond along the way.
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 common theme is friendship. Ash and Greninja's relationship is often at the center, showing how they rely on each other and grow together. For example, in many stories, they face challenges that test their bond and come out stronger.
Well, in Alola, the battle environment is different. Ash Greninja has to adapt to the new battle rules like Z - Moves. It may start by observing local battles and learning from them. It could also adapt to the more friendly and less intense battle atmosphere compared to other regions. This means it might have to change its battle strategy a bit, not always going all - out from the start. And it might interact with different types of Pokemon that are native to Alola, which could lead to new friendships or rivalries, further shaping its adaptation to the Alola environment.
One common theme is the bond between Ash and Greninja. It often shows how they grow together, trust each other, and face challenges as a team. Another theme is Greninja's evolution and how it affects their relationship.
They might have an epic battle against a common enemy together. Greninja could show off some new moves it has learned during their separation, and Ash could use his experience from other adventures to lead them to victory.
In this fanfiction, Greninja might come back with new powers. Maybe it has been on a special training journey and returns to Ash to help him in a big battle.