Tiny microscopic virus-like creations of supernatural evil that are the source of zombie plagues.
Tiny microscopic virus-like creations of supernatural evil that are the source of zombie plagues. They infuse a person on a cellular level while he's still alive, and almost instantly begin to propagate throughout his body. Unlike mundane diseases, the demon germs can not be cured by traditional medicine, and could only be detected as odd cellular aberrations. Faith and Theurgy can provide deterrence while alive, but once dead the person is doomed to return as a husk.
Due to the infusion of demonic energy on cellular level, the person is able to still move despite massive damage and decay. Also, while this energy keeps protects the body from decomposing bacteria and parasites, it also causes the host to slowly lose his mental facilities and self-control. I strongly suspect that once the person's mind is completely gone, so too is his soul (consumed by the Dark).