Prerequisite: Swarm subclass, Warlock level 6

Your swarm attack can deal necrotic damage rather than piercing, and on a hit the target suffers a level of exhaustion unless it already has one or more levels of exhaustion.

Additionally, when you spend one minute adjacent to a corpse that has died within the last hour, you can regain hit points equal to your warlock level. Once you have used this ability, you cannot use it again until you've taken a short rest.