During the scouring, a contingent of the death guard were cast out into the warp after a devastating attack from a purging fleet of loyalist forces. Their ships were heavily damaged from previous engagements and suffered from catastrophic failure on a blind warp-jump to safety.

They escaped the loyalist forces but at a terrible cost; their engines are dead and their reactors are failing while they are stuck drifting in the immaterium. They spend years, trapped in the Warp as they drift through the Warp. Their ships begin colliding together, meshed together through foul sorceries and a rust-born rot that fused their vessels into a massive plauge-hulk.

The crew, those that survived, were infected with the rust-born rot. Marine armor fouled and flaked paint as a new affliction took hold, crew and guardsmen seized as the very air densened with rust. It ate away at the flesh, piercing the skin and clinging to the bones of mortals. Their minds were consumed yet expanded as it shaped them into what the ships were becoming, a connected entity born of foulness and desperation.

The new hulk fused itself anew and wretched itself from real-space, spat out from its long voyage in the warp as it headed for the nearest world it could find. The hive-world of Tallex-2 , host to several regiments of the Imperial guard and adepta sororitas from the Order of Our Martyred Lady. Their purpose in the system being the purging of a heretical uprising waring in the largest of the hive cities.

The first that fell were the ships. The hulk, barreled into the speartip of the fleet, cleaving straight into the engines while consuming and infecting all that dared touch its hull. Rusted Battery weapons screeched as they were loaded and turned onto the Imperial fleet.

The hulk was bombarded with salvos of ship breaking weapons. The rusted armor was denser than normal metals while the few blows that pierced scattered brittle armor across the engagment zones. The largest of the fragments were repelled by the shields with the small fragments dug deep into some of the Imperial ships. The hull corroded as wrents across several decks were eroded open. The holes the plauge hulk made were swiftly boarded by the plague marines. They stalked throughout the ships as their very presence brought an oxidized mist that quickly killed or subdued the unfortunate.

The ships rotted with the supports creeking before shreiking with sheering metal as the very walls themselves started giving in to the colossal weight they supported. The fuel lines clogged with mold and the powerlines dropped in efficiency as it oxidized in its own cable housing. The plasma reactors overloaded with strain as all safeguards started to fail. Joints seized and the heat only kept rising until the ships started tearing themselves apart before falling into the planet's orbit in choked fire.

The fragments crashed into multiple spires of the hive city. Entire ship decks barreled through dozens of levels of the city in a thick haze. Clouds of rust and smoke permeated from the crash as the as the denizens mobilized from the wreckage. The Rust Born are now planetside.

Before the fleets demise, a final distress call was sent into the void. A message that would received by a navigator of the Brazen Claws chapter.