Ysylas served the role of a basic Feral World priorly, being of little importance to the Imperium. The planet was however helped out after a large amount of deaths in the planet's climate. Ysylas was often raided by nearby Orks afterwards, stealing technology and making life harder for the inhabitants every time, returning to sister-planet Isolum afterwards.
Taking note of the attacks, the Imperium tracked down the Orks to Isolum, and immediately dispatched a nearby chapter, the Knights of Redemption. The Knights of Redemption quickly dispatched of the Orks, leaving little of worth, apart from a captured vehicle and a few relics, behind at the planet.