Body Jumpers

The Exorcists are by far the best at hunting down and eliminating the Body Jumpers. They have been waging a near constant war with these nefarious evil-spirits who target those closest to the Exorcists. They watch the Exorcists, study them, jumping from body to body as they slowly stalk their prey.
In return, the Exorcists have kept an extensive wealth of knowledge regarding the Body Jumpers. They know everything about their makeup, their habits, their weaknesses and fears. The Exorcists have devised several methods and powers specifically for combating them.