Arrizon is a world in the Eastern Union a coalition of worlds in the Eastern Fringe; cut off from the Imperium by long-lasting Warp Storms, they were forced to join together for self-defense.
Arrizon was settled long ages before in the Dark Ages of Technology, and brought to the Emperor's Light in the time of the Great Crusade. A peaceful Agri-world, the native nations lived, largely untroubled by the outside universe.
Eastern Union Civil War
Many of Arrizon's tribal leaders were partial to the Confederation of Darkness, and in 200.M37 declared their world for the Confederation: in a swift campaign, they overran most loyal forces on-planet, contributing troops to the Confederation army elsewhere.
But Union forces swiftly counter-attacked: reinforcing troops from the Western Reach, primarily from Bearf, landed in 201 and joined with native loyalists: in a short, nearly bloodless campaign, they drove the rebels to the fringes of the world; though intermittent guerrilla war went on for the rest of the war, it was nowhere near the bloody level of Missery or Ketuck, and Arrizon remained firmly in loyal hands throughout the rest of the war.
Arrizon was the unfortunate world to first discover the presence of Necrons in the Eastern Union when, in 999.M37, Necrons entombed there awoke; their rising devastated the planet, burning much of the once-fertile world to desert. The Necrons then set out to slaughter all of Arrizon's populace.
The tribal chiefs hurriedly armed their people and formed them into militias to fight the irresistible metal tide while Union Army reinforcements under General Edward Canby were rushed in from all over the Eastern Union. In bitter fighting, they succeeded in halting the Necron onslaught, then Canby counterattacked, sending a picked force of Rough Riders to attack and destroy the Necron Lord at the Battle At The Foot Of The Pyramids.
Once a peaceful agri-world, Arrizon's inhabitants now scrape and struggle to wrest a meager living from the desert sands.
The razing of the world however revealed previously-undiscovered veins of precious metals; in the years following the war, settlers came to Arrizon seeking fortune; they often clashed with the native nations, leaving a legacy of bitterness that has weakened the world.