It has been reported that the dragon-ground Kalos legendary Pokemon, Zygarde, has multiple forms.
According to Coro Coro (translated by Pokebeach), the flattened green blob "forme" is referred to as "Zygarde Cell Forme" and there are a number of them disseminated in many places. When multiple Zygarde Cell Formes unite with the green blob formed seen in July, the "Zygarde Core Forme" will arise. It is said to be the brain of each subsequent formes.
The union of multiple Zygarde Cell Formes and a Zygarde Core Forme will result to the formation of the "Zygarde 10% Forme," which looks like a dog and has inconceivable speed and sharp fangs. It was not indicated if its typing deviates from the dragon-ground typing of the original Zygarde.
The original Zygarde in the Pokedex and the video games will be called "Zygarde 50% Forme," which is the same to Sinnoh dragon-ghost legendary Giratina's "Giratina Altered Forme." It is assumed that "Zygarde 50% Forme" is either a blend of its previous forms or a combination of many cell forms along with one core forme.
The mysterious Pokemon's silhouette in previous reports has been revealed as the "Zygarde Perfect Forme." The Pokemon stands 4.5 meters tall and weighs 610 kg while keeping its dragon-ground typing. Since it is a blend of its other forms or a number of each, Zygarde Perfect Forme is viewed as more powerful than the other two Kalos legendary Pokemon, Xerneas and Yveltal.
Meanwhile, Ash's Greninja will have its different form in the new anime series called "Pokemon XY & Z" and it is called "Ash Greninja." According to Serebii, Greninja's new look resembles its trainer Ash; however, no further information has been revealed behind its form change.
It is assumed that fans will see Zygarde's multiple forms, along with Ash Greninja in "Pokemon XY & Z," which comes with "Mega Evolution Act 4" on Oct. 29.