One interpretation of a fifth horseman is the representation of pestilence, as a separate entity along with conquest, war, famine and death. The underlying idea is that pestilence and disease have ...

As per the Bible, the Four Horsemen of the Apocalypse are Conquest, War, Famine, and Death. However, as time passed, Conquest was replaced with Pestilence as early as 1906 in the Jewish Encyclopedia.

he discovers a terrifying link between a chain of murders and the Biblical prophecies concerning the Four Horsemen of the Apocalypse: War, Famine, Pestilence, and Conquest.