In most cases, Orcus transforms his followers into undead creatures such as ghouls and wights. Sometimes he needs his followers to retain their mortal forms, to more easily infiltrate a kingdom or city. He grants rank-and-file cultists the Undying Soul trait, and his cult leaders gain the Aura of Death trait.
Undying Soul (Recharges after a Short or Long Rest)
If this creature is reduced to 0 hit points, it immediately makes a DC 10 Constitution saving throw. If it succeeds, it is instead reduced to 1 hit point.
Aura of Death
This creature emanates a deathly aura that extends 30 feet in every direction from its space while it isn't incapacitated. The aura is blocked by total cover. While in the aura, the creature and any friendly undead are immune to the frightened condition and have resistance to radiant damage. Enemies suffer disadvantage on death saving throws while in the aura.