Hello everyone. In case anyone hasn't heard yet, there have been some new forms of the Kalos Legendary Pokemon, Zygarde that have been revealed. The Anime News Network has just released some pretty detailed information about these forms. It seems to be more information than the serebii.net site seems to have. A link to the info on ANN can be found below.
So from the looks of it, Zygarde is actually a Pokemon made up of multiple organisms that are distributed throughout Kalos, with the "Core" acting sort of like a central processing unit. The article on ANN also seems to imply that there's more than one "Core" In a way, Zygarde could be thought of as a sort of automated defense system designed to protect the environment of the Kalos Region. When the "Core" or "Cores" detect some kind of threat to the environment, they respond proportionally by gathering the surrounding "Cells" and taking the form best suited to deal with the threat.
There's currently no information on how these new forms will appear in the games, though I imagine that they'll show up in a later game called Pokemon Z. I'll try and report more new details as soon as I learn about them. One thing I will say though is that Zygarde has become one of the most fascinating Pokemon I've seen in a long time.