Oz gotten infected like the other characters. They are drugged by Atlas so they can kill all the zombies. Atlas started all of this. Oz has a Sentinel Symbol on his right arm. He is the source of the infection. He got shot in the head by Lennox but he's still alive but now he is a zombie. He was a Janitor before the outbreak. When he got shot he became 76% Infected and 24% Human. Oz nicknames are Patient Zero because he is Patient Zero.