The Underhives of its enormous Hive Cities contain lakes of toxic waste and refuse. Their wretched populations dwell in terrible squalor within archipelagos of hovels and shanties, mounted on discarded girders to hold them above the viscous fluids. The Underhives also suffer from brutal gang warfare and as a result of both, almost everyone there dies of sickness or at the gangs' hands. In M42, however, a widespread outbreak of a Nurgle mutation occurred in the Underhives, that resulted in the dead rising once more. The populations of Goranl's upper Hive levels responded by merely having the Underhives sealed off and then posted additional Enforcers to guard the entrances.
In time, though, hordes of infected Mutants and Undead broke through the Underhives' entrances and began swarming the Hive Cities. With their Enforcerss and PDF unable to keep them at bay, Goranl's Imperial Commander was forced to sent out a plea for aid. The Sons of the Phoenix serving in the Wardens of the Gauntlet would arrive to help, but by then much of the Hive World's order had been lost. However this did not dissuade the Space Marines and the Sons attacked the hordes with unremitting fury. They refused any respite, in order to maintain their momentum and as the Sons advanced, holy armies of men and women, singing the Emperor's praises, followed them. Together, this great host of crusaders began putting Goranl's infected Underhives to the torch. Such was their infectious faith, that many of the Hive World's exhausted Enforcers and PDF troops spontaneously joined them, with renewed zealous energy. With the Sons of the Phoenix leading the way, Goranl was purged of the Mutant and Undead hordes that had threatened it.