The Great Devourer had consumed many galaxies beyond the Milky Way and encountered many extraordinary life forms. Broadly speaking, they fell into two categories.
One category cost biomass to consume, as when fighting the Necrons; the other yielded biomass, as when fighting humans. Strangely, there was also a third category: Orks. Fighting them yielded vast quantities of biomass, but the battles were brutally difficult and only grew harder as they went on. The Tyranid Swarm often suffered heavy losses under Ork attacks.
The Milky Way was unrivaled in its strangeness. Not only were the civilizations of the material realm peculiar, but beings known as warp daemons also existed in the realm of souls.
These daemons were made of energy, born from the emotions of living beings. They existed to harvest mortal souls and often competed with the Tyranid Swarm for food!
The Kronos Hive Fleet was the Great Devourer's answer. Unlike other Tyranid fleets, this fleet was designed specifically to fight warp daemons.
The swarm organisms in the fleet specialized in ranged attacks, supported by large numbers of psychic Tyranid organisms intended to suppress the Warp's influence on reality. This approach had proved highly effective in several recent battles against warp daemons.
Previously, when the Chaos Warmaster Abaddon destroyed Cadia, the wildly expanding Great Rift had exerted a tremendous influence on realspace. An enormous Tyranid fleet had happened to lie directly in its path, and the expansion had inflicted devastating losses on it.
The Tyranid fleet had originally been large enough to deliver a fatal blow to the Imperium of Man. Because of the Great Rift, however, the Great Devourer had been forced to continue stockpiling biomass and expand its fleet once more.
For the Great Devourer, the Tyranid Swarm's position on the battlefield in the Ork Sector was far