The Primordials

The primordials are an ancient myth, born hundreds or perhaps thousands of years ago. It focuses on the ancient civilization found the old village of Prima, one of the oldest known villages in the world.
In Prima, a man named Ravvar Syker discovered an old skull, perfectly intact. No one can tell exactly when it’s from, but everyone guesses it’s from a time before written history, as nothing has ever been described like it before. It resembled what they knew to be their skulls, only with one large eye socket instead of the three typical ones. It was ovular in shape and didn’t seem like anything they had known of before. No sketches existed before the discovery, and no mention has ever been made in any textbook or history book.
The people thought the worst. There were ideas of a nasty plague wiping out an old race, ideas of a huge war with them coming out on top, and even going as far as saying they’re still alive, deep in the caves no one dares venture into. The people eventually came to the idea that they came from another planet, far off into the stars. 
It’s become a huge conspiracy that everyone has heard, but not many people think about it often. It’s a fairy tale, a hoax. No one has ever seen more skulls since, so everyone believes Ravvar sculpted it out of clay to fool people. No one could figure out why he would do that, but for a long while, that's what many believed to be true.

Many years later, it was speculated that maybe the current Gemclops had evolved from them. Multiple skulls had been found in Prima after a geological study that matched the rumored one Ravvar had found all those years ago. No one has done any research since. The kings of the world deemed it to be unimportant. If beings were living in the caves, they would never be found. If there were aliens, they wouldn't come back after being killed off so harshly. Maybe sometime in the future, they would decide to look into it more, but for now, it remains a mystery to the world.