Erm... I don't know if this is known be alot of people yet, but iv'e found out that Shaymin's Sky Forme, Rotom's forms and Giritina's Origin Forme will be in HG and SS. Also I have found where Deoxys is able to change forms.
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Shaymin's Sky Forme was also introduced in Pok
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Shaymin's Sky Forme was also introduced in Pok