Negative energy

Negative energy was a type of energy originating on the Negative Energy Plane. It manifested as a black, crackling surge of power. It was the antithesis of positive energy, being the "lifeforce" of undead creatures, while causing harm to the living.

Clerics
Clerics were adept at using the power of negative energy. It was the power of negative energy that evil clerics channeled to awe or command undead, and it was used in the inflict series of spells (e.g., inflict light wounds,) to injure living beings.