Revelation 9:15-18

So the four angels, who had been prepared for the [appointed] hour and day and month and year, were released to kill a third of mankind. The number of the troops of cavalry was twice ten thousand times ten thousand (two hundred million); I heard the number of them. And this is how I saw the horses and their riders in my vision: the riders had breastplates [the color] of fire and of hyacinth (sapphire blue) and of brimstone (yellow); and the heads of the horses looked like the heads of lions; and from out of their mouths came fire and smoke and brimstone (burning sulfur). A third of mankind was killed by these three plagues—by the fire and the smoke and the brimstone that came from the mouths of the horses.