Following discovery of the last known location of the UNSC Spirit of Fire from the Battle of the Etran Harborage, the Office of Naval Intelligence sent the UNSC Taurokado to investigate the system for any information regarding the whereabouts of the lost UNSC warship.
The Assassination of Avu Med 'Telcam was an assassination sanctioned by the Office of Naval Intelligence Section Three and carried out by SPARTAN-G059 on the leader of the Servants of the Abiding Truth on former colony world New Llanelli in the Brunel system in January 2558.
The Battle of Sunaion was a battle between the Swords of Sanghelios led by Thel 'Vadam, their allies Fireteam Osiris led by Jameson Locke, the last of Jul 'Mdama's Covenant forces, and the Created forces led by the Warden Eternal in the state of Sunaion on the Sangheili homeworld of Sanghelios.
AboutAfter the Covenant fell, many leaders tried to take control of what remained and make their own place in history. The remnants were many and fought for power many years following the fall of the Covenant.
The Sangheili-Jiralhanae War
The end of the Human-Covenant War did not end conflict between species or even within species. Since the war was ended by the Great Schism, fighting between the Jiralhanae and Sangheili was initially significant and resulted in the destruction of much of the former Covenant fleets. As the might of the Covenant faded, however, so did much of the conflict of the Sangheili-Jiralhanae War. While the conflict never had an official end, most of the fighting had ceased within a year of the end of the Human-Covenant War.
Swords of SangheliosThe last Covenant Arbiter, Thel 'Vadam, and his Sangheili allies were instrumental in helping the UNSC win the Human-Covenant War. Once the war ended, he quickly tried to cement his political and military power at home, but faced stiff resistance from many Sangheili groups who didn't like 'Vadam's newfound alliance with the humans. It was that very alliance, however, that ultimately allowed the Swords of Sanghelios to emerge victorious over all other former Covenant factions late in 2558.
Jul 'Mdama's Covenant
'Mdama was by far the most successful former Covenant member to command a fleet and uncover Forerunner artifacts for his advantage. Jul's motivations stemmed from early in the post-war era, when he was captured by the Office of Naval Intelligence, and his wife was killed during fighting with Thel 'Vadam's forces on Sanghelios. After 'Mdama managed to escape from ONI's grasp, he found a fundamentalist group of Sangheili and proceeded to recruit them on his quest of revenge.
Keepers of the One Freedom
In 2553, Castor, a Jiralhanae Chieftan and Dokab of the Keepers of the One Freedom, led a pack of Brutes onto the human colony world of Gao and attempted to take control of a Forerunner ancilla located within one of the cave systems of the planet. Although he had help from insurrectionists on the planet, Castor's plans were thwarted by the actions of Spartan-II Blue Team, as well as a handful of Spartan-IIIs and the UNSC 717th Xeno-Materials Exploitation Battalion.
Later in 2553, the Keepers' base of operations was nuked by the UNSC after a kidnapping was staged to appear to be carried out by the Keepers rather than the actual perpetrators, Dark Moon Enterprises.
Servants of the Abiding TruthAs soon as the Human-Covenant War ended, there was a struggle for power on Sanghelios between the Arbiter Thel 'Vadam and those who opposed his idea of ceasing war with the humans. One of the first and strongest factions to rise to power were the Servants of the Abiding Truth, a deeply religious group led by Avu Med 'Telcam who still revered the Forerunners as gods. Their actions early in 2553 nearly toppled the then fragile rule of Thel 'Vadam, and likely would have succeeded were it not for the intervention of the UNSC Infinity in support of 'Vadam. The Servants were forced to flee to the former human colony world New Llanelli, where 'Telcam was eventually assassinated in 2558.
When the Great Schism ripped the Covenant apart, most of the San'Shyuum, aka the Prophets, fled and were not heard from again. One exception was The Minister of Preparation Boru'a'Neem and the Prelate Tem'Bhetek’s Faction, who devised a plan to strike at the Sangheili in 2553. Using Tem'Bhetek's superior strength and intelligence, they led the CAS-class assault carrier Shadow of Intent, commanded by Half-Jaw Rtas 'Vadum, into a trap with the intent of killing everyone on Sanghelios. The plan was nearly successful, but was thwarted through the actions of Rtas 'Vadum and his crew.
In 2554, a Sangheili Zealot by the name of Merg Vol had gathered up a large fleet of former Covenant vessels and followed the word of a Forerunner oracle to the moon of human colony world of Draetheus V. There, Merg Vol found not just a human presence, but a Forerunner device capable of destroying planets. While Merg Vol's forces did manage to gain control of the device, known as X50, the actions of Spartan-IVs Sarah Palmer and Edward Davis along with the UNSC forces stationed at the colony, were able to stop Merg Vol and his forces from destroying the planet.
There have also been several events in the Halo universe that have not yet been pinned on a specific faction or group formerly associated with the Covenant. These attacks, while seemingly random, are no less destructive than those perpetrated by any known group.