The Composers were pieces of Forerunner technology that were created by the Forerunners in order to gain a foothold against the Flood in the Forerunner-Flood war. They are capable of bridging organic life and digital technology together. One was used by the Ur-Didact on ancient Humans, adding to his legion of digitized beings called the Prometheans. The Composers were originally intended to allow the Forerunners to become immortal. The Didact pursues this piece of technology in Halo 4.