Ecumene Council

The Ecumene Council was the main government and lawmaking body of the Forerunner ecumene. It was located at the Capital. When referencing the Council, a distinction is often made between the Old Council and the New Council, the former's transition to the latter being defined by a major shift in governance and Master Builder Faber's exile around a decade before the end of the Forerunner-Flood war.

Led by the First Councilor, the Council was composed of five hundred Councilors from various rates. The Councilors typically served for a thousand years and took vows of abstinence and austerity. This was apparent in the general aesthetic associated with the Council; their ships and residential facilities lacked luxury or adornment, yet reflected the Council's status and power. The Council was supported by a network of ancillas known as the Council metarchy.

The Council had its own dedicated security force known as Council Security; additionally, special forces known as myrmidons served to protect high-ranking members of the Council. The Council metarchy also maintained significant contingents of embodied military-grade ancillas of various types aboard Council ships and other facilities. While normally dormant, the machines would assist in the defense of the Council during an attack, and were capable of substituting for biological Forerunner commanders in an emergency.

History
During the human-Forerunner wars, the Council was affected by the growing influence of the Builders, whose power and wealth continued to accumulate as they supplied increasingly more weapons to fuel the war effort. The Council began to lose many of the Forerunners' old ways and ideals, becoming more ruthless and economically-driven. This general corruption led to humanity's exceedingly severe punishment after the Forerunners' victory. The Builders' power continued to consolidate gradually over the following millennia due to the political maneuvering of the Master Builder, Faber, culminating around 101,000 BCE with the exile of the opposing Prometheans, leaving Faber and his like-minded Builders virtually in complete control of what would later be known as the "Old Council".

However, around a thousand years later, the Old Council underwent a radical change. After the Master Builder used a Halo to commit a genocide of the San 'Shyuum, not even Faber's allies in the Council could justify what was considered a crime against the Mantle, and a revolutionary party of younger councilors opposed to the Master Builder took command. With word out that the Didact had returned, he was called upon to be restored in command while Faber was put on trial before the Supreme Mantle Court. During the proceedings, however, the rogue AI Mendicant Bias staged a massive attack on the Capital and eventually fired a Halo in the system, killing most of the Old Council; however, a number of councilors managed to survive deep within the Capital.

After the Forerunners' reconquest of the Capital system, the survivors of the Council were reconstituted into what was now referred to as the "New Council", which continued to function for several years. After the Flood took over the Capital system, the remaining Council members escaped to the greater Ark with the Master Juridical. There, they agreed to restore the Master Builder in command of Forerunner defense, as his Halos provided the only remaining defense against the Flood. The final dictum issued by the Council, before its destruction at the Battle of the greater Ark, ordained the deployment of the final Halo installations in their designated locations across the galaxy and the protocols involved with the assignment of the installations' respective monitors.

List of appearances

 * Halo: Cryptum
 * Halo: Combat Evolved Anniversary
 * Terminals
 * Halo: Primordium
 * Halo: Silentium