Talonflame and Greninja Page 1.

I know we will see Ash's Greninja again one day. Usually whenever Ash releases one of his pokemon, they will reappear in the show again, in one form or another. Let's take Ash's Charizard for example. Ash released him at Charicific Valley so he could become stronger. He wasn't seen in the anime for awhile, with the exception of Ash's battle with Noland, his pokemon league battle with Gary & the events of The Spell of the Unown. Charizard, years later, joined his trainer in Unova and developed a friendly bond with Ash's Pignite. After Unova, he has remained in Oak's lab since. So as of right now the only possible scenario I can come up with, where Greninja could possibly return, is while Ash is in Alola, at some point in the series (and spoiler alert btw to those who haven't played Ultra Sun or Ultra Moon yet), Necrozma appears in an episode or in a movie & causes so much chaos because it's angry (just like in the games) that Ash and his friends have to find a way to stop it. This would probably be caused by Team Skull or Faba out of revenge for what happened to them. And when the part where Ash gets put into a life threatening situation, Greninja appears and saves him. He will also team up with his old trainer to combat the threat. This would also be the part where we could potentially see Ash-Greninja again & if one or all of Ash's friends are nearby, they would probably be shocked at the sight. Nebby also would make a reappearance as well & Necrozma would force-fuse with it to make Dusk Mane Necrozma. Ash & the gang defeat it & it sinks back through a wormhole, presumably to the Ultra Megalopolis. This would also be the part where Ash & the gang meet the Ultra Recon Squad & they call upon Lunala to take them to Ultra Megalopolis to go and confront Necrozma, since Nebby is unavailable. The gang goes up the tower and sees Necrozma as Ultra Necrozma. They engage in a battle. By this point, Ash has a Poipole (spoiler alert again btw) who knows Dragon Pulse (even though Ash's Poipole has not learned that move yet. But it could be taught to it or it learns it on its own prior to these events. Also, Dragon Pulse is a required move for it to know if it wants to evolve into Naganadel) & sometime during the fight, Poipole evolves in Naganadel. So long story short, the gang defeats Necrozma, frees Nebby, & returns back home. What would be a good reason for Greninja to return to the show? Since Ash's Greninja is still with Z-2 and Squishy, both Zygardes sense danger from afar in Alola from Kalos. So they send Greninja there to see what's up and take care of it. Zygarde also appears in all the Gen 7 games so it would make sense for it to be a key factor in this. Keep in mind, this is just my prediction so don't take it so seriously. So what do you think?