Revelation 9:7 And the shapes of the locusts were like unto horses prepared unto battle; and on their heads were as it were crowns like gold, and their faces were as the faces of men.
8 And they had hair as the hair of women, and their teeth were as the teeth of lions.
9 And they had breastplates, as it were breastplates of iron; and the sound of their wings was as the sound of chariots of many horses running to battle.
10 And they had tails like unto scorpions, and there were stings in their tails: and their power was to hurt men five months.
11 And they had a king over them, which is the angel of the bottomless pit, whose name in the Hebrew tongue is Abaddon, but in the Greek tongue hath his name Apollyon.
12 One woe is past; and, behold, there come two woes more hereafter.
In verses 7 through 11 John gives a description of the demons that appear as locusts they are as big as horses, crowns to show they rule, faces like men to show their intelligence. The long hair had a seducing effect to draw men near, the teeth like a lion to help inflict pain. Their breastplates made them indestructible and the sound of their wings was like the sound of a mighty army coming. And if this is not enough to terrify man they also could sting them like a scorpion and all of this torture was to last for five months causing man to want to die. Again they had a leader through all of this and to put it simply it was Satan. This is only the first WOE and there are two more to come.