Why are the Greys called Terrans since that would mean from Earth?? since the other name for Earth should be Terra as in Terra Firma ("solid earth" in Latin)
Try not to read too much into it. In this story, they are Terrans. People from Earth are Humans. As in people from Pantheria are Pantherians. And Echo (Ecko) is a Teldarian from Teldar. Acladeans from Acladia.
If you want to really get that technical about it, the Pantherians and the Acladeans are in effect a society that have joined forces to support each other. Therefore, the Acladean Rebels are still rebels since they defy their own kind as well as the Pantherians.
