Automated units built by the planet Cravic to fight the Pralor, which destroyed their creators and kept the war going on their own.
The Cravic automated units are robots built by the people of the planet Cravic to wage war against the planet Pralor, which had built automated units of its own. When the two worlds called a truce and tried to shut down their machines, the robots destroyed their makers to preserve themselves and continued fighting.
In Prototype, Torres was abducted by a Pralor unit and forced to build a prototype that would let the Pralor reproduce. When a Cravic ship attacked, she learned the full history and destroyed the prototype rather than tip the balance of the endless war.