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, descriptively referred to as a Sublimation Device, was a machine created by the Forerunners to translate an organic being's mental content into machine data. The device originated as one of the first of the countless failed plans laid by the Forerunners to defeat the Flood. While its failure to save Flood victims quickly led to the Composer being abandoned in this capacity, it was later used for a number of purposes beyond its original function.

Overview
After the Forerunners first discovered the existence of the Flood parasite in the later stages of the human-Forerunner wars, they quickly began to devise plans to combat the infection should it resurface. The Composers were one of the first solutions proposed by the Builders. The original function of the machines was to save Flood victims by extracting their mental patterns—or essences—and translating them to data by broadcasting high-energy fields of entangled sympathies. The stored essence would then be imprinted on a new, artificially constructed biological body devoid of Flood infection. However, the process was highly flawed. In addition to being extremely painful to the individuals undergoing the process, all attempts to restore the essences to biological form failed as the artificial bodies would quickly decay and inevitably die. For this reason, the Forerunners quickly abandoned the Composers after the first experiments.

The physical effects of the Composer on its targets were also violent: the device projected a beam of orange light which completely reduced the targeted individuals to ash in a rather gruesome and painful manner. This is seemingly a byproduct of the machine's original design as a means to combat the Flood, allowing the complete destruction of infected biomass in a manner similar to certain Forerunner weapons designed to completely atomize their targets. The beam possessed the capability to process hundreds of thousands of targets in mere moments across enormous distances, such as composing targets on a planet's surface from an orbiting ship, or those on the surface of an entire Halo installation in an instant. Lord of Admirals, the supreme commander of all human forces and one of the humans to have their minds harvested, described the effects of the Composer as "strange, ever-changing" and "multiformed", as it operated via intermediary Lifeworker machinery.

As witnessed on Installation 07, Flood victims subjected to Composer processing were able to retain their individualities, but the Flood would continue to rot and deform their physical bodies, the infection having survived the destruction of the original biological body and then resumed in the new one. The Forerunners attempted to slow down this process by wrapping the afflicted individuals' bodies in a form of supportive harness flowing with energy, but the victims would still continue to deform beyond recognition and eventually expire or succumb to the Flood. Similarly, when the Gravemind used corrupted, Composer-processed essences imprinted on living human bodies as messengers to the Librarian in her final moments on Earth, the humans' bodies would rapidly decay and soon die.

Essence preservation
Minds scanned by the Composer could be processed in a variety of ways. The ancient human personalities extracted and stored by the Librarian at Charum Hakkor retained their essences in virtually unchanged form, preserving the victims' identities and even the records of their physical bodies, although the latter in seemingly incomplete form. These stored personalities could also be implanted into the genetic code of living beings, with said personalities achieving self-awareness and retaining their original identity within their new hosts; an example of this are the ancestral memory imprints of Chakas and Riser. The Composer could also be used to remove these imprinted personalities, although this did grave physical and mental damage to the individual carrying the imprint.

In the case of the Ur-Didact's Promethean Knights, the extracted neural map was used as the basis for artificial intelligence constructs in a manner similar to the creation of human smart AIs. These intelligences contain many of their original memories and sometimes even portions of their personality, but otherwise behave within the limits of the duties assigned to them. These essences were stored in imprint matrices known as Durances, similar to the devices traditionally used to contain the last mental impressions of a deceased Forerunner.

Immunization
The Composer did not work on all organic beings; certain individuals could, through genetic manipulation, become immune to its effects. After undergoing and experimental mutation in an attempt to gain immunity to the Flood, the Ur-Didact's physiology was no longer compatible with the Composer. Similarly, the geas the Librarian placed on humanity allowed the Spartan John-117 to develop a resistance to the Composer; this ability had to be activated, and thus it did not automatically protect all humans from the device.

Use at Charum Hakkor
Developed by the Builders during the human-Forerunner wars as a countermeasure for the nascent Flood, the many faults of the Composers were quickly recognized. However, despite the failure of the original plan, the Forerunners found other uses for the devices.

After the fifty-three-year siege of Charum Hakkor, the strongly Builder-influenced Old Council intended to exact their vengeance on their human enemies and make sure the humans' fate would be as cruel as possible. Thus, even though the Forerunners already possessed other technologies capable of extracting an individual's memories and personality impressions, the Council only provided Composers for the Librarian and her Lifeworkers when they were ordered to process the last human survivors. The essences of the archived humans would be preserved in future generations of humans, with the intent that they share their knowledge with the devolved remnants of humanity and aid them in rebuilding their civilization. The Master Builder and other like-minded Forerunners intended to study the stored memories in hopes of discovering how humanity managed to defeat the Flood, subjecting machine-stored copies of the essences to tortuous interrogation over thousands of years.

Abandonment and later use
As a result of the risks and irregularities involved with their usage, the Forerunners eventually abandoned the Composers and their existence was made a closely guarded secret known to only a few. Even the machines' actual nature remained obscure; whether the Composer 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 Lifeworkers no longer employed the long-abandoned Composers when scanning sentient beings for indexing in the Conservation Measure, instead using a far gentler form of pattern extraction technology.

A Composer was acquired and used by Master Builder Faber in an attempt to stave off Flood infection in certain Forerunners on Installation 07. 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 Erde-Tyrene.

Later during the war, the Didact used the Composer to convert the Promethean warriors loyal to him into robotic forms 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 number of humans transplanted to Omega Halo, turning them into additional forces in his mechanized army. This led to his imprisonment on Requiem by the Librarian.

Rediscovery
One Composer was stored on Halo Installation 03. In late 2554, the UNSC Office of Naval Intelligence discovered the machine, designated as SBJ 8490-03, on the Halo ring and transported it to Ivanoff Station, a research facility in the asteroid field in Installation 03's orbit. The machine was partially buried within the installation's surface and remained embedded in a large chunk of rock when the UNSC transported it to Ivanoff. Some of the scientists were digitized by the Composer while studying it and the sensor data from the incident contained coordinates that led the to Requiem.

Upon awakening on Requiem in July 2557, the Didact immediately headed for the Composer and acquired the device after launching an attack on Ivanoff Station. Planning to use the Composer to neutralize all of mankind by forever imprisoning them into digital form, he first used it on the human personnel of Ivanoff; Spartan 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. He successfully fired the Composer on a URNA metropolis, New Phoenix, 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. Some of the resulting digital intelligences survived, having ended up on Requiem via a slipspace transit portal connected to the Composer.

List of appearances

 * Halo: Primordium
 * Halo 4
 * Halo: Silentium
 * Halo: Escalation