Hollow

A hollow is a living body without a spirit. In losing their spirit often these unfortunate individuals often loose much of what made them human, leaving them dim witted and easily controlled. In the first few years after their transformation little can seem to change other than slowly becoming more absent minded. The lucky ones can remain in this state for much of their remaining lives. Beyond this honeymoon period Hollows often cannot survive without direction, slowly loosing the motivation and intelligence to sustain themselves. Hollows that last more than a decade start to take on a aura of dread and repulsion, the sheer unnatural length of their lives antithetical to those who cling to life. 
There are several ways one can loose ones soul, yet most are lost to time. The most common consists of rituals and rites that strip the soul from the body, this can either be done to those willing or unwilling. Those seeking knowledge of demons often throw themselves into pacts they barely understand in hopes of power and prestige. Others whisper of curses and phenomenon out in the wastes that can do the same, and others in hushed tones speak of the one that controls The Hoard of organised hollows that roam the docks. 
Hollows also contain one final trait that makes them extremely valuable to some. When specially prepared and presented forward they can be possessed by a particularly powerful Ghosts and when they fuse the result is a Vampire. At this point nothing more of the host remains other than the shell that holds the power of the vampire.