While we don't actually know what the next mainline Pokémon game will be, we have some details on new forms and such.
First, I have to make sure everyone is acquainted with Zygarde. Presumably, Zygarde is the third legendary, a la Rayquaza, Giratina, and Kyurem.
Default Zygarde (the one you can catch right now on an X/Y cartridge) is apparently the "50% form", whatever that means.
We've been waiting for over a month to find out what Zygote actually was, and he's called "Zygarde Core", and is basically what is controlling all the different Zygarde forms.
Then we have his new "10% form", which is a dog.
And his final form is his "100% form", which is the pope.
All forms are Ground/Dragon to my knowledge.
Then we have a new form for Greninja, which might be his Mega, but probably not. All the other Megas for multi-stage Pokémon incorporate design elements from their prevolutions, so you'd expect Mega Greninja to have, like, bubbles.
The magazine specifically mentions Ash, as well.
i think this all sounds STUPID