"They, primarily orion and sirius have been here for thousands of years... They are responsible for genetically manipulating the planets inhabitants, and setting up hierarchial structures on this planet, where the true top of the pyramid is orion..."

i have read much about this, and if true, then it is staggering that they came here when there was a choice of 400 billion stars in the milky way for them to visit.

if they did arrive, then they later left and went to check out other star systems, using their star-gate technology.