Banished

The Banished are a faction of warmongers, mercenaries and raiders originating as a Covenant splinter faction. Founded and Led by the Jiralhanae Atriox, the Banished are predominantly made up of his species, although Sangheili, Unggoy, Kig-Yar, Lekgolo, Huragok, and even Humans are present within their ranks, along with various vehicles, aircraft and weapons of both Covenant and Jiralhanae design. The Banished originated as little more than pirates, but exploded in power after the Human-Covenant war, claiming many of the fallen Covenant's assets.

History
Originally, Atriox was a Chieftain serving in the ranks of the Covenant, leading his troops as expendable cannon fodder against the enemies of the Covenant. Atriox developed a reputation for surviving numerous suicide missions, as well as a hatred for the Covenant for sending him and his pack to die for a religion they had no belief in. Concerned about the possibility of an inssurection, the Prophets of the San'shyuum set Atriox up to fail an impossible mission and arranged for his ceremonial execution known as banishment, considered a spiritual exile from the Great Journey. However, Atriox instead killed the executioner and incited an open rebellion against the Covenant. Afterwards, he fled with as many Jiralhanae who would follow him. For the duration of the Covenant's war with the UNSC, the Banished raided numerous Covenant holdings for weapons and supplies.

When the Covenant collapsed in 2552, the Banished grew exponentially as they absorbed a great deal of its remnants, including a CCS-Supercarrier known as the Enduring Conviction. As made evident to the Sangheili Shipmaster of the Conviction, Let 'Volir, as well as a group of Sangheili assassins known as the Silent Shadow, the Jiralhanae representing the Banished leadership had no quarrel with the Sangheili as they were not involved in the Covenant's genocidal betrayal that resulted in the great schism, as well as Atriox's dismissal of the feud between the two species. By 2559, the ranks of the Banished swelled with countless Jiralhanae warriors, Sangheili mercenaries, enslaved Unggoy and even Lekgolo colonies of different formations from those permitted in the Covenant. Reportedly, Human criminals have also served as agents of the Banished.

After the Created unleashed the Guardians upon the Milky Way galaxy, the Banished discovered the extragalactic Forerunner installation known as the Ark, where the Human-Covenant war ended. The Banished massacred the Human scientists left stranded in the wake of the Created and claimed the Ark for themselves, although the Sentinels reacted violently to their salvage and mining efforts. Eventually, the UNSC ship Spirit of Fire, having been lost with all hands after the Battle of Etran Harbourage almost 30 years prior, drifted into orbit above the Ark and the newly awakened crew and marines quickly found themselves at war with the Banished. By their intervention, the Banished lost control of the Ark's teleporter network, Atriox's lieutenant Decimus was killed and the Enduring Conviction was destroyed. In a last ditch effort, the Banished attempted to sieze control of the newly assembled Halo installation 09, but it was disarmed by the UNSC forces and departed to replace installation 04, leaving Atriox and his forces stranded on the Ark with the Spirit of Fire.

Six months later, the Banished sought an escape from the Ark by salvaging for functional ships at the crash site of High Charity, previously the capital city of the Covenant before it was claimed by the Flood and destroyed by Spartan-117 during the Human-Covenant war. Dismissing the Flood as little more than Covenant propaganda, the Jiralhanae commander Voridus defied Atriox's orders and breached the quarantine measures surrounding High Charity, unwittingly unleashing the Flood trapped within. Despite the immense cost to their forces, the Banished successfully slew the Proto-Gravemind and aided the Sentinels in driving the Flood back into High Charity.