Death's Head Rebellion

The cause of the collapse of the First Empire of Man in the tenty-seventh century was a war of extermination fought between the 'old style' humanity and the bio-engineered Sauron Supermen, creatures who walked like men. thought like battle computers, and fought like demons. Though humanity eventually annihilated the home world of the Saurons, the cost was high; the Emprie fell into a new Dark Age in which the secret of interstellar travel was lost for centuries. So when a remnant of the Saurons escaped to a world called Haven, the merely human inhabitants should have been easy prey for the superhuman newcomers. But the Saurons hadn't anticipated a mutiny in their own ranks leading to a three-cornered war.