In ufology, Greys, also known as Roswell aliens, Zetas, and Reticulians, are aliens or extraterrestrial life forms that appear in purported modern-day encounters and other UFO-related paranormal phenomena. Said to be one of several species of aliens, greys make up approximately 75 percent of all aliens reported in the United States, 20 percent of all aliens reported in Continental Europe, and 12 percent of all aliens reported in Great Britain.
Typically, Greys are described as being either approximately four feet tall with grey (sometimes blue-grey/green-grey/purple-grey) skin. Their body is typically described as being elongated, and lacking in muscular definition. Their legs are shorter and jointed differently than one would expect in a human, giving them an apparently awkward gait. Their arms often reach down to their knees, and some accounts give them three digits, or three digits and a thumb on each hand. They have a bulbous, hairless head supported by a thin neck, which is dominated by large, (usually black) lidless eyes. They typically have small flat noses, small mouths and no external ears. In some cases, Greys are said to have slit-like nostrils on a flat face. Some accounts have Greys wearing tight neutral colored uniform-like jumpsuits. Other reports have them appearing to be naked. In most cases, clothed Greys have no determinable gender and naked Greys have no visible external genitals. Greys reportedly absorb food as well as excrete waste through the skin, which makes them emit a foul odor.
In Slayer Advance
The Greys appear in the episode "Visitors" in which the slayers are warned about the impending destruction of humanity on Earth. It is not until the second series "Slayer: Darkness Conspires" that the Greys play a more frequent role. The Greys are later found out to be the creators of the slayers. The Greys were at war with demons and overthrew them thousands of years ago. The demons fled to Earth and settled there. The Greys recovered from the war's destruction and decided to intervene in the crisis now on Earth. The Greys began a prgram to create a genetically advanced human that could fight and keep the demons at bay. Humans were given Grey DNA which resulted in the Slayer line. Strangely, it only affected females. The Greys also trained and informed ancient human civilizations on combatting the demons. The Shao Lin monks and the Mayans were the first civilizations contacted. Attempts at contacting the ancient Egyptians failed due to demonic interference. The Greys are said to return to Earth in 2012 to aid the slayers in the complete eradication of all spirits and demons in a final war.