Vectors of Contagion: The Eight Realms are not the natural environment of daemons. In spite of their power, they rely on vile acts perpetrated by mortals to aid their emergence and subsistence on the material plane. The Rotbringer Contagiums are Nurgle’s chosen tools in this regard, sowing the death and decay to which the Grandfather’s daemons are drawn like carrion beetles to a reeking corpse.
Each time an enemy unit is destroyed by an attack made in the combat phase
by a unit from this battalion, you receive 1 contagion point