Every now and then a person dies, but their body lives on. This is not death in the usual sense, their organs continue to function, they breathe perfectly normally as any creature does. This is worse than death as everything that made them who they were, made them human, is gone. these wretched soles, often wrapped in rage and anger, seek vengeance for that which was taken from them, that which created them. An innocence stolen or a life brutally taken, the reason fading with each victim they consume replaced only by the emptiness and darkness of the predator that grows within.
Nothing could break the cycle of the wretched lone wolf… except…maybe… meeting another.