There are also non-playable Survivors that players will meet throughout the campaigns. At the start of the first campaign in Left 4 Dead 2, the playable characters have just met each other and do not even know each other's names. In Left 4 Dead, it is never explained how the Survivors met up with each other, or how long they have been together (although judging by the timing given by the intro cutscene and The Sacrifice comic, it is less than 12 days by the start of the first campaign). In addition, The Sacrifice comic presents the hypothesis that the Survivors are Carriers of the Infection―and as such are a positive danger to any uninfected humans they encounter. Although the playable characters are immune, a comment by Bill suggests that they could become an Infected at any point. The term, however, is commonly used to refer to the eight playable characters from the Left 4 Dead game series. The Survivors are people in the world who have not contracted the Infection (either by virtue of being a carrier or possessing some form of immunity). The Left 4 Dead 2 Survivors, from left to right: Coach, Ellis, Nick, and Rochelle in the Dead Center poster. The Left 4 Dead Survivors, from left to right: Francis, Bill, Zoey, and Louis in the No Mercy poster. ' That's right, we should call ourselves the Unstoppables!' ― Louis ' We're the four riders of the goddamn apocalypse!' ― Nick

Left for dead poster