Revelation 9:11-15

Their king is an angel from the abyss, whose Hebrew name is Abaddon, and whose Greek name is Apollyon. The first horror has passed. Look! Two horrors are still coming after this. Then the sixth angel blew his trumpet, and I heard a voice from the four horns of the gold altar that is before God. It said to the sixth angel, who had the trumpet, “Release the four angels who are bound at the great river Euphrates.” Then the four angels who had been made ready for that hour, day, month, and year were released to kill a third of humankind.