Battle of Ryza
Aimed at Ryza home to one of the most important Forge Worlds in the Galaxy, the battle was decades in the making as Grax's Boyz gradually pushed the Imperium back across the System. Emergency reinforcements being raised for the Imperial Guard proved ineffective, and Grax continued his advance, swallowing planet after planet in bloody conflict. The Ork forces enslaved the population of worlds they conquered, such as Proctus Prime. Other worlds were mined for their resources to fuel Grax's Waaagh!, such as the Mining World of Hyberia. Only newly arrived reinforcements of Catachan Jungle Fighters avoided total Imperial collapse. The Catachans held the world of Ulani IV, though two other nearby planets and three moons orbiting Barac fell to the Greenskins. Eventually, Grax's forces managed to reach Ryza and invade the planet twice, thrown off by desperate Imperial defenses each time.
As bitter fighting raged across a hundred fronts across the Ryza System, an entirely new Waaagh! materialized in the region, drawn to "great fight" that was taking place. The ragtag fleets of Kommander Rarguts broke through the Imperial Navy's blockade of the System and began to threaten Ryza itself. Rarguts deployed squadrons of Fighta-Bommers to clear way for his advance of Stompas, Gargants, and Boyz. The Legio Crucius Titan Legion, supported by massive amounts of Imperial Guard Regiments, continue to put up a vicious resistance yet still the Orks advance.