Death is the Green Horse of the End and a darkness spirit. He is symbolized by a scythe.
The Four Horses of the Apocalypse are four horse guardian spirits who are said to bring about the end of the world in order for it to later be reborn anew, therefore inspiring many apocalypse legends in various religions. Legends say that the apocalypse has happened many times before and only the fittest survive, guardian spirits being among them. It's members include Conquest, the white horse of victory; War, the red horse of chaos; Pestilence, the black horse of famine; and Death, the green horse of the end.