CODEX: THE KOVENANT IMPERIAL ARMY.

The Iron Knights.

Out of all the units employed by the Imperial Army, not many can be as powerful as the so called "Siege breaker battle suits" and their users, while no official military name had been given to the unit, the soldiers often referred to this stomping giant as the "Iron Knights"

Iron Knights are specialist soldiers within the Kovenant Imperial Army, who have been trained to use the Siege breaker battle suit to fight as a mobile weapons platform and as a devastating assault asset within the service of the Army.

Recruitment.

The recruitment of this warriors was very low indeed... The reason for this is, while there are many eager recruits, only a select few humans actually have the mental capacity to operate such a complex machine.

The Siege Breaker battle suit operates by connecting the Battle Suit's own on board "machine spirit" or AI as the Cult of Hephaestus termed it.
This is because it is impossible for any humans to effectively operate this suit within being connected to the motor systems of the suit in question. Once connected, the soldier wound feel the suit as if it had become their body, allowing them to use it naturally since they literally have control over the suit itself and drive function and the men can leave their suits after the battle had concluded.

As a result of this, recruits for the Iron Giants are very slim pickings indeed and when such men are found, they are typically valued above all else, as this would be the rare individuals who were often the men and women chosen to operate Siege Breeker battle suits.

This is because said recruits have something which is known as the "Siege Breeker gene"
This is an incredibly rare form of natural, mental mutation that typically affected the brain area more than any other part of the body, and it gave this people the ability to seemingly "meld" their minds with any and all AIs that they are expected to link themselves to.

The exact origins of this gene is unknown, however it is likely that it was part of a long lost and forgotten experiment during the legendary
"Golden age of man.", before the time of the Kovenant Empire, when the old human federation was known to have started testing and experimenting with all manner of different mutations, before collapsing into a 1000 year long Dark age of war, carnage and unimaginable death and destruction that would not be rivaled again until the present day... From the ashes rose a new power and thus, stood boldly the Kovenant Empire.

Effectively meaning that this gene predates even the modern day Kovenant Empire by a millenia.

In an attempt to increase recruits, the Cult of Hephaestus, with the support avd approval of the Kovenant Imperial Army as well as approval from the Reichstag and the Kaiser himself... The Cult of Hephaestus attempted to increase the number of recruits by attempting to ensure that the mental capacity to operate a Siege Breeker battle suit is passed on to the next generation and in particular, their children.

To do this, the pilots often underwent biological modifications, including creating a "trigger" mechanism, which had one purpose: it was designed to try and copy the ability of the parent to operate the Siege Breeker suit and to copy that unto their children, via, mutating the brain of the child as they were being grown inside the wombs of their mothers.
Effectively attempting to copy the Siege Breeker gene into their offspring.

The end result, was an entire sub group of humanity known as
"Siege Breaker operators"
The off spring of those who had operated the battle suits and have been training all their lives in order to one day join the ranks and help ensure that they can carry on the legacy of their parents, in a manner similar to knighthood.