Composer

''This article is about the machine. For the Halo 4 level, see Composer (level); for the achievement, see Composer (achievement).'' "The Composer! So many possibilities and capabilities tied up in that strange name... A Composer of minds and souls!"

- Forthencho, Lord of Admirals

The Composer was an ancient Forerunner machine capable of converting living beings into digital forms.

Overview and function
The Composer was created by the Forerunners to save them from the Flood by allowing them to transcend biological forms altogether, granting them virtual immortality as digital intelligences. However, the Forerunners never perfectly mastered this capability and the resulting digital personalities became corrupted or fragmented and could no longer be restored to biological form. The Composer was also capable of slowing down Flood infection and the subsequent loss of individuality; however, this process was only temporary and still left the afflicted individuals in their deformed state. Physically, the Composer was an enormous, monolithic artifact engraved with patterns of lines characteristic of Forerunner architecture.

History
The first known use of the Composer was when the Librarian employed its primary capability by extracting the memories of the surviving human warriors after the Charum Hakkor campaign in order to store their memory impressions in future generations of humans. The Lord of Admirals, supreme commander of all human forces and one of the humans to have their minds harvested, never saw the Composer directly and described its presence as "strange, ever-changing" and "multiformed", as it operated via intermediary Lifeworker machinery.

As a result of the risks and irregularities involved with its usage, the Forerunners eventually abandoned the Composer and its existence was made a closely guarded secret known only to few. Even its actual nature remained obscure; whether it was a machine or being remained uncertain to most. Some even believed the Composer to be a "product of its own services"; a Forerunner, perhaps a Lifeworker, suspended in the final stages of Flood infection.

Around 100,000 BCE, the Composer was used by the Master Builder to stave off Flood infection in certain Forerunners on Installation 07 to keep them in a docile state. After initial processing with the Composer, a form of harness prevented the infectees' decaying bodies from breaking down. While in control of Installation 07, Mendicant Bias and the Primordial also used the Composer to extract the ancestral memory imprints from Chakas and the other humans from Earth. Later during the Forerunner-Flood war, the Didact used the Composer to convert his Promethean warriors into robotic forms in order to allow them to combat the Flood more efficiently and without risk of infection. To bolster his numbers, the Didact used the Composer on a human population on Installation 07, turning them into additional forces in his mechanized army.

The Composer later ended up in an asteroid field orbiting Installation 03. After the end of the Human-Covenant War, the United Nations Space Command Office of Naval Intelligence discovered the machine embedded in an asteroid and set up a research facility known as Ivanoff to study the artifact. Upon awakening on Requiem in 2557, the Didact immediately headed for the Composer and acquired it. Planning to use the device to neutralize all of mankind by forever imprisoning them into digital form, he first used it on the human personnel of Ivanoff; John-117 was the only survivor as a result of genetic modifications imbued by the Librarian. The Didact then set course for Earth in order to realize the final stage of his plan. The Didact successfully fired the Composer on a major city in North America, but the effect was halted when John-117 destroyed the Didact's ship, and the Composer along with it, with a HAVOK tactical nuclear weapon.

List of appearances

 * Halo: Primordium
 * Halo 4