>>40478656The anime personally requested Ash to get a Mega Evolution for a Gen VI Pokemon; the issue is that, aside from Mega Diancie, there weren't any Mega Evolutions for Gen VI Pokemon. Ash didn't have a Diancie, and the last game with new Mega Evolutions (ORAS) was released the year before. So the anime staff worked with Game Freak to give Ash a pseudo Mega Evolution for one of his Pokemon. Greninja was chosen because as a starter, it is the most popular of Ash's Pokemon at the time. As such, Greninja, who rarely had that much development in its earlier two stages and was phased out for other Pokemon, got a shit ton of backend development once the seventh gym started. Instead of retconning Greninja to have a Mega, since Game Freak didn't want any new Megas in SM for Z-Moves, they used a different gimmick where Greninja can "Mega Evolve" without a Key Stone or a Mega Stone. This concept worked well in the demo, as Ash-Greninja got people to download this demo and eventually buy the main game so they can transfer this exclusive Pokemon over.
Charizard wasn't even on Ash's team when the concept of Megas were introduced fully in the anime, so he doesn't need a Battle Bond form.
