DEROS/TEROS
There are also underground civilizations of non-humans that have been referred to as Deros and Teros. The Teros are more friendly and help keep the Deros, who are more demented, from having excessive power. They live underground in tunnels, cities and sometimes under the sea. Most of the legends of the past of leprechauns and trolls refer to these non-humans from the inner earth. The Deros are competitors with the Greys, but they have similar qualities and cannot be trusted.