The Asuwang 

A mystical entity that has existed in the universe without the knowledge of the Endless themselves. They have advanced well beyond other civilizations and and developed techologies allowing for exploration and expansion before most, but instead of taking over and making their empire clear, they choose to do so in silence and shadow, watching other civilizations grow and fall. They have done so for eons, seeing the universe develop through time but have never acted to impart any change, simply just watching, observing the universe and it's inhabitants. They occasionally insert themseleves into societies, albeit, under the cover of invisibility  and will observe their civilization up close. Nobody can truly pinpoint why they just watch. Some say that they are simply waiting for something or maybe they intend to act as the archivists of the universe. The real question is,  why would they suddenly make their presence known now?