Potential spoiler - Here's how I imagine Z-A's climax
For those who've followed the teraleak and all the news in it you may remember that not only we got a confirmation of "mega Zygarde" existing but also the notion that Zygarde was created with in mind the idea that he can change form depending on the threat: Zygarde 10% (wolf) is the counterpart to Xerneas (deer) while Zygarde 100% (hunter) is Yveltal's (eagle). So my theory is that, to oppose Lumiose City ill-made urban redevelopment, Zygarde will take this brand new form. What's the opposite of artificial and man-made? Nature, a tree, the Yggdrasill.
For those who've followed the teraleak and all the news in it you may remember that not only we got a confirmation of "mega Zygarde" existing but also the notion that Zygarde was created with in mind the idea that he can change form depending on the threat: Zygarde 10% (wolf) is the counterpart to Xerneas (deer) while Zygarde 100% (hunter) is Yveltal's (eagle). So my theory is that, to oppose Lumiose City ill-made urban redevelopment, Zygarde will take this brand new form. What's the opposite of artificial and man-made? Nature, a tree, the Yggdrasill.