The Murii Overwatch Regiments initially started as a Planetary Defense Force for the little known mining world called Murus. In M31, warp storms opened within close proximity to Murus, and daemons were believed to have made their way to the Murii solar system. By M32, the farms which had sustained Murus had failed. While it is unknown what caused the crops to die, many attribute it to the nearby warp storms. Rebellion ensued, and wars over scraps of food crippled Murus. With the mining industry utterly disabled, the planet's only export was was no more. Widely regarded as a useless "pile of rock" by most nearby planetary governors, no help was issued and Murus was forgotten. The planet was engulfed in chaos. Dark agents had set up countless underground cults with which starving peasants came to in eagerness. By M36, the PDFs lost complete control over most hive cities, and were driven out to the sulfer ash wastes or Murus.
In 337.M37 PDF General Dominic Vibius, a figure widely respected by PDF forces, renounced the planetary governor and simultaneously marched his loyal PDF forces on every hive city. Entire populations were massacred mercilessly. Hellhounds were deployed as Riot tanks. Grenadier squads infiltrated underground chaos cells and destroyed them. Demolisher tanks supported by brave guardsmen assaulted the cities, supported by artillery barrages from Earthshaker batteries. Within 300 years, Domonic Vibius single handedly brought order to an entire planet.
Not only had he made the Murii Overwatch a skillful urban fighting force, but he reformed the entire military system on the Planet. This completely transformed the Murus PDF into an elite, respected, and skillful fighting force. The 27th was among these honorable fighters.
Regimental Banner of the glorious 27th: