Death Master

Type: Transdimensional / Death Cult
Death Masters are human beings who are immune to zombie-causing virology but are still carriers for the disease. They can infect other humans, who almost always become Zombies themselves, unless the infected happens to be another rare carrier of the Death-Master. 
Death Masters are genetically modified individuals who serve the Death Cult. Changed via the application of arcane Death magicks, they utilize the Undead as a weapon in the hands of the Cult itself. 
Official documentation includes written reports, several of them by military personnel and experienced Adepts, of certain human beings seen walking unharmed amid Zombie mobs or hordes. Not only have these people remained unharmed or ignored by the Zombies, but at times they've even been able to command the Undead and direct them like a captain leading a team. 
Death Masters appear perfectly human and cannot be detected apart from normal human beings without specialized genetic screening tests. Masters who have been activated can be detected by looking for the Zombie causing virus within their bloodstream.
Death Masters are dangerous because they can slip past quarantine barriers to spread the disease or they can direct existing Zombies, giving them organization and crude strategy during a purging action on the part of military forces or the actions of the Adepts.