The Deer King, Vol. 1 (novel)

Van, a former soldier made slave, toils away endlessly in a salt mine. An expected chance at liberation drops in his lap when a pack of infected dogs pass through, killing everyone but him and a young girl called Yuna. Van hopes to make a peaceful life for himself now that he's escaped. However, the disease that cleared out the mine is rapidly spreading, placing him and his ward at the center of a conflict greater than any the world has ever seen.