Forsworn

Once a promising loyalist Space Marine Chapter, aspiring to great accolades and glories, the former Astral Consuls fell into a tragic downfall of ill fate which led to the destruction of their beloved home-planet of Costov, as well as the branding of the Chapter Excommunicate Traitoris and declared Renegades. Struggling to not fall into the temptations and worship of the Ruinous Powers, the grief the Astral Consuls were finally brought to be servants of Chaos by a Dark Apostle by the name of Kazrand the Illuminator. And thus, the Space Marines renamed themselves "The Forsworn" in mourning of their home Costov.

Now a fearsome Chaos Warband that roams around Imperial Space like ghosts, ever hunting their hated enemy of the Inquisition that destroyed Costov due to accusations of stealing xenos relics under the Inquisition's jurisdiction.

The Fall of Costov (245.M36)
Created during the 20th Founding in late M35 to reinforce the regions of space in the Chiros Sector of Segmentum Tempestus, many details of the Astral Consuls' gene-seed and campaigns have been classified by order of the Inquisition. However, during their time, the Consuls were noble and fierce on the battlefield, performing their duties with admirable efficiency, including the destruction of an alien planetary civilization known as the Aeur. But as the Aeur were noticeably utilizing the powers of Chaos, the Ordo Xenos had accompanied the Astral Consuls into the battle to destroy the Auer.

During the war against the Auer, it was noted by both the Consuls and the Ordo Xenos that the xeno warriors seemed to shimmer strangely and even teleport seemingly at will. And due to the reliability of the usage of this, it was surmised that the Auer had somehow created stable teleportation technology. And after the alarmingly bloody campaign for a single planet, the Inquisition took many corpses and bits of the Auer's creations with them to be studied, or destroyed.

It would not be very long, however, that the Auer artifacts would remain in the hands of the Inquisition. Shortly after being transported to the nearest Inquisitorial Vault, the entire complex was suddenly attacked by a force so mighty that all inside the Vault were dead in minutes, and the Auer items taken. After it was discovered the raid had occurred, recovered pict-feeds showed what looked to be Space Marines with a color scheme matching that of the Astral Consuls. With this news, a fleet of the Ordo Malleus was called to the Astral Consuls' homeworld of Costov to confront the Astartes.

Confused and outraged at the accusation of breaking their honor and stealing from the Inquisition, most of the Chapter vehemently denied the crime of raiding the Inquisitorial Vault, but their firm resistance had only sealed the fate of Costov. Failing to submit to the Ordo Malleus' demands, the Fleet's guns were fired upon the planet- beginning an Exterminatus. Attempting and failing to fight back, the Astral Consuls forced to flee into the Warp to escape the guns of the Inquisition.

In grief and rage, the remaining of the Astral Consuls Chapter drifted in the Warp for years, realizing that the very Imperium that they were created to- were pledged to serve had now cast them out. For those many long years travelling in the Warp, Chapter Master Arkann Dionus sat silent on his throne on the Chapter's Battle Barge, Angel of Storm, until suddenly another Astartes suddenly appeared before him, as if from thin air. The strange Space Marine identified himself as Kazrand, and as a friend. Kazrand, the Word Bearer, comforted the crestfallen Arkann with confident assurances, such as "We are all too similar, my child. I too, have felt the burning wound that is betrayal by one's supposed superiors. But... there is always a choice- always a decision to avenge the wrong done to you and your brothers, your WORLD."

And so, Kazrand began the work of reunifying the Astral Consuls into great sermons to the Chaos Gods, and demonstrated that if they would be abandoned by the Imperium, then they would abandon it and be granted far greater powers, and avenge Costov.

The Return of the Forsworn (273.M36)
When the Imperial Navy became aware that an alarming number of ships disappearing throughout the Chiros Sector, a Fleet was sent to patrol in force. But when the said fleet returned to Navy Command, only three ships returned, all heavily damaged. The crew of each ship was in a panicked and terrified state, wildly repeating that, "a legion of ghosts have come to take us away." However, there was a singular command deck attendee was lucid enough to deliver a message to Navy Command.

"Those that have been wronged have returned. Those that once served will no longer be bound by tyrants. Those that have lost their home will take yours. Those that were once Marines of the False Emperor, are now the Forsworn. Those that have been betrayed will become great, your worlds burned, your people butchered, your idols defiled, your corpses giving way for more worthy life, insects."