I look on these canisters, so deceptively innocuous, and I shudder. My scribe Demetrius, who is learned in the arcane script of the Engineers, has deciphered the glyphs on these cylinders, and tremblingly informs me that herein the Guilds have trapped the incorporeal souls of those demons who haunt the lowest hells: those malignant entities who bring the tumor-sickness and scorch entire worlds in flame of such virulence that the planet is thereafter anathema to Urthly life.