What's the difference between Greninja and ash Greninja?
Similarly, how does Greninja turn into ash Greninja?
Greninja that can become Ash-Greninja have an Ability that no Pokémon has ever had before—Battle Bond. The Battle Bond Ability triggers this Pokémon's form change to Ash-Greninja after it causes an opponent's Pokémon to faint. When the battle ends, the Pokémon returns to its original Greninja form.
Subsequently, question is, is Ash Greninja better than Greninja? Ash-Greninja hits harder, but is more predictable. Plus there's the fact Ash-Greninja is locked with 128 evs in its offenses, while regular Greninja isn't. And you have to actually ko something first. Plus there's the fact Ash-Greninja is locked with 128 evs in its offenses, while regular Greninja isn't.
Also, does ash still have Greninja?
Greninja was released by Ash to battle against Sawyer and his rival Grovyle, who is now evolved into Sceptile, and both appear as their third and final evolution.
Why did Greninja leave ash?
Greninja was released because he wanted it to help out Zygarde with cleaning up the Kalos region. Goodra was released because he was concerned about its friends in the wetlands. Charizard got left in the valley so that it could become stronger on his own without battling.