The Sires Origins are yet uknown but one thing we do know is that they were created by a researcher named Niles Samson. Samson was also a controller of security at the New Hope Research Facility. When Marcus and Dom enter the Facility, Niles rambles and talks about the security and cleanliness of the Facility. Later, it is revealed that Niles was creating creatures he called Sires and that he had done something on Mount Kadar involving them. In letters from different New Hope researchers, it seems that Niles did not realize how dangerous the Sires were and that he called them, "his children".
