Changes

A field test for the first thousand sets of [[Space Marine]]s equipped with [[Power Armour_#Mark 6 "Corvus Armour"|Mk.VI]] [[Power Armour]](provisionally dubbed the Mk V at the time, as the [[Power Armour_#Mark 5 "Heresy Armour"|armour that eventually bore that designation]] had not yet been developed), the campaign was waged against the [[Eldar]] of the [[Scalland Sector]]. [[Raven Guard]] forces were chosen to conduct the operation despite their recent heavy losses in the [[Akum-Sothos Cluster]]. There is some speculation that certain Imperial commanders led by [[Perturabo]] pushed for the under-strength and bloodied Raven Guard to conduct the field tests in hopes of their failure and thus the cancellation the Mk.VI project, which Perturabo hoped would spur the development of a new heavy assault variant.{{Fn|1}}

However if that was Perturabo's intent, the plan backfired as the Raven Guard performed admirably against the Eldar forces. They used their advanced auto-senses and increased agility to hound the Eldar in a series of hit-and-run attacks. Originally just intended as a field test, the Raven Guard were actually able to expel the Eldar from the Sector altogether. As a result of their success, the Mk.VI armour was approved for mass production. In the Raven Guard's Primarch [[Corax]]'s honour, it was dubbed ''Corvus'' Armour.{{Fn|1}}