The Nerushimi Ironclad are Imperial Guard Regiments from the fortress world of Nyerushimiy, an isolated, far-flung world at the edge of the segmentum obscurus. With the Nyerushimiy system isolated from the Imperium by vengeful and unpredictable warp currents in all but a sparse few well-charted vital areas, the Ironclad have been forced into disparity and struggle by ever-present threat of chaos, having been forced into fierce industrialisation, austerity and self-devised tactics and technologies forged off the back of their own ingenuity in the absence of Imperial foreign aid in their efforts to survive.
First born from the World's Revolutionary army, the Astra Militarum of Nyerushimiy experienced a cancerous growth through the need to defend against Chaos, in addition to the Administratum's ceaseless demands to industrialise and produce surplus weapons, artificially birthing a cycle of endless economic boom for the ruling elite as more and more weapons could be produced, used and destroyed in war, and replaced.
Following the eventual disappearance of chaos's afflicting hand, surplus weaponry could no longer be justified, and the core source of the ruling class's fabulous wealth was threatened. This eventually led to first contact with the outside Imperium, first hinted as a possibility through Rogue Trader fleets, and later actualised through official contact with the nearest Imperial worlds. With the realm of the far future being a theatre of unending war, the possibility of fighting beyond the planet's limits was an opportunity the world's rulers simply could not ignore.
Nyerushimiy fields 120 fully-functioning Imperial Guard regiments known as the Nerushimi Ironclad. As heavily mechanised drop regiments with concrete morale records and deep-set, wrought tactical approaches forged from a lifetime at war, the Ironclad have grown to be a demanded force throughout the Segmentum Obscurus amongst many thousands others, and lately, have seen service in other entirely different Segmentae.