13 Bullets takes place in Pennsylvania in the year 2003, in a setting similar to the real world, but where vampires and other supernatural forces are rare but accepted phenomena.

Their ears become pointed, their hair falls out, all teeth become wickedly sharp, and skin color always becomes pale white, regardless of ethnicity and pigmentation in life.

The vampire must remain in a coffin during the day, as their bodies literally die each sunrise, and flesh melts into a noxious fluid, with dead skin and maggots.

In one scene, Arkeley tells Caxton, that the half-deads are "cowards" and are very easily frightened, though they seem to stand their ground despite massive casualties in later encounters.

They exhibit increased speed and vastly enhanced physical strength (enough to twist open a steel padlock using bare hands).