Adam suddenly felt overwhelmed by so many emotions as he stumbled backwards onto the ground as his biggest fear was becoming true.
He had remembered the bodies of the 5 dead men that were tortured and remembered that Angela Maxwell had told him that evil methods would use the negative energy that was emitted by humans that were experiencing extreme negative emotions.
That could be done through torture, sexual assault and many other ways and they would do so to suck in the life force and energy of the target, which could be absorbed by the Evil Cultivator as negative energy.
There was negative energy in the atmosphere in the same way that there was positive energy, but almost all humans were unable to absorb it into their bodies like positive energy.
However, through evil methods and by committing evil acts, an evil cultivator would be able to create negative energy and suck it out of their target's body and into their own.