Militarum Psykers and the Vault wars.

History of the Vault Wars.

After a time in the vaults of Prime the newly forged Militarum felt the wave of corruption wash over the planet’s surface, the wave came from the nearby portal to the corruption realm, with this communication from the higher vaults went dark with the waves passing. The vaults below the dark vaults started to send forth expeditions to the lost vaults above with gruesome results.
The higher vaults were discovered to be wrought with mutations and malfunctions that made them become insane and start worshipping the dark magics that turned them into creatures of dark design away from the normal forms they were brought here with from their old world. First to be seen by the expedition was the ghoulish humans that flesh was melting from their body and an odd 'radiation' came from the creatures. This radiation reeked of corruption energies and the creatures had no remembrance of what they were before the change becoming mindless beasts.
The expedition sent for reinforcements to assist with the cleansing of the strange creatures but it was difficult for the peoples of the world that were use to more simplistic life after becoming less militaristic when they merged into one people and fled underground. They needed a new plan to regain their prowess in battle and a way to defend themselves against the corruption and twisted creatures above.
Within the great machine that provided them with the vaults they found the mechanics to make armour and weapons that would assist them with the task of dealing with the corrupted ones. They kitted themselves into their new weapons and power assisted armour and prepaired for the war to come.
The war started with ease the new armor and weapons cleaving and blasting their way onwards through the dredges of corrupted creatures making good ground and reclaiming a few of the vaults. But the further they went to the surface the stranger and stronger they creatures became. Hulking brutes that had also started to make armour for themselves and had enough intelligence to steal the new weapons from the attackers started to come down on the Militarium. Not only did the new creatures have the intelligence to use the weapons the Militarium dropped, but the corruption embodied within their core allowed them to manifest strange and un-godly powers that caused the militarium to have to retreat and rethink their strategy.
They started to consult the great machine below on how to stop this new power the corrupted ones had with little result even with the retrieval of test subject to help with the discovery of the basic understandings of corruption. But with more research revealed a hole that they could take advantage of, the energies left over from the blast and that of the energy in the bodies of the ones they killed can be harnessed without initially becoming corrupt themselves. They could wield the power of the enemy against them. But for how long before the energies fade away and become exhausted.
They couldn’t focus on that they had to rid the planet of the corrupt and regain their lost vaults.
So the battles started again. With the militarum focusing on using the new arts against the corrupted ones with a new understanding of the corruption they worked endlessly on the battles forcing the corruption back as far as they could until they reached the surface.
But it was not like the history books proclaimed. The city in ruins the land scorched and sundered by un-known energies that left the world un-inhabitable. This was when the machine gave them the last key to their future. Vaults opened to the surface to show ships that they could fly away from their dead world with.
They prepared to leave the world on the ships there was enough for the whole of the militarum to get onto and leave the world behind. As the people prepared to leave they noticed the last of the corruption energies were spent. They had no more link to the corruption realm to reach the power they learnt to use in the heat of battle but they still had the machines armour and weapons that until the present are still being used as relics of the great war bestowing greatness and pride to the militarum of today.
But with recent events of asteroids being fuelled with corruption energies the militarum see a chance to regain the prophesised powers of old and retake the power they fought tooth and claw to claim from the corrupted ones of old. All they need to do is claim one of the asteroids for themselves and they can once again wield the power.

Measures against corruption

With the dangers of the wielder turning into a corrupted one there is a special force of militarium named the Purge. The purge troop work to route out the corruptions weak points and learn how to combat the corruption and those that succumb to the darkness.

Manifestation

The militarum manipulate the energies of corruption to come forth in their battles in a red or gold hue of light.

"Great loss was felt when we lost the power of the ancients but we will reclaim our right and our power to fight back those that raise our ire!" Supreme Elder of the Militarum

Type

Metaphysical, Demonic