Feral human/doc
Ferals are a diverse group of humans who have completely lost their minds due to the events of the Cataclysm, they are remnants of the original rioters during the early stages of the Cataclysm. They are always hostile and are treated as friendlies by zombies. As expected from their infection, they will inevitably become zombies either when killed and left to revive or over time. To learn more, check out the Dealing with Ferals guide.