Cross reference
Revelation 9:18
18 By these evils a third part of men was put to death, by the fire, and the smoke, and the burning smell which came out of their mouths.
Revelation 9:15
15 And the four angels were made free, who were ready for the hour and day and month and year, that they might put to death a third part of men.
Revelation 9:17
17 And so I saw the horses in the vision, and those who were seated on them, having breastplates of fire and glass and of burning stone: and the heads of the horses were as the heads of lions; and out of their mouths came fire and smoke and a smell of burning.