The Four Horsemen are the Manifestations of Christ's Presence for all to SEE. "For just as the lightning comes out of the east and shines over to the west, so the PRESENCE of the Son of man will be." (Matthew 24:27)
They are part of the Composite Sign Jesus answered to the question, “Tell us, when will these things be, and what will be the sign of your presence and of the conclusion of the system of things?” (Matthew 24:3)