With at least one nearby corpse, you and nearby Allies deal 10% more Damage
With at least one nearby corpse, nearby Enemies deal 10% reduced Damage 
Plaguebringer is a Notable Ascendancy passive skill for the Necromancer that grants the you and your minions increased area of effect if you've consumed a corpse in the past 4 seconds. In addition, while near a corpse, you and nearby allies gain more damage while nearby enemies deal reduced damage.
The more damage and enemies deal reduced damage buff is coded as auras. The player character, the allies and the enemies would have visual aura effects on them.