Talk about it here.
The Drofen were once fierce warriors, but eventually signed a galactic treaty agreeing to only carrion. They began scavenging worlds looking to consume their dead. They would often land during a war and covertly consume the bodies of those killed in battle.
Thousands of years after the galactic treaty, a Drofen ship landed in Stalingrad during World War II. They began consuming the dead and the living. Erimem called for the Drofen to return the living and dead they had stolen and return to space. When the Drofen leader refused, she instructed Yuri Kurkov and his soldiers to bomb their ship. (PROSE: The Beast of Stalingrad)
The Drofens returned in the future after they were thought extinct. They wiped out all life in the Venulatu system, and then went on to attack the Andromedan Princess, killing all on board. (PROSE: Absolution)