If triggered too rapidly in PvE, monsters will flee the AoE.
Combine Dark Aura with touch or point-blank skills that require sacrifices such as Signet of Agony and Touch of Agony. Other sacrifice skills, touch skills, or point-blank skills, particularly Demonic Flesh, may also work well.
When cast by multiple characters on the same ally, the one with the highest Death Magic will govern the damage dealt, but the health lost by each character will be divided by the number of casts. For example, one character has 16 Death Magic and another has 0, and they both cast Dark Aura on a third character. When that character sacrifices health, 53 damage will be dealt, the character with 16 Death Magic loses 11 health (half of 21), and the character with 0 Death Magic loses 2 health (half of 5).