The awful destructive judgments of the Trumpets and Vials that are to come upon the earth are for the purpose of weeding out the worst of the human race, so that only the righteous through Christ shall be saved for the millennium.
The Plague of Infernal Calvary was for two reasons, retribution and reformation.

         To punish the idolatry and demon worship of men, and their sins of murder, sorcery, fornication and theft, and to keep others from following in their ways.

                    But it appears that those left, who were not killed, didn't repent and turn from their sins and were left for later judgments.
The invasion of the Infernal Cavalry has awful destruction. They slay a third part of man.  If that means of the whole world and it's present population, they will destroy around a billion people.

        Another thing, the four angels were prepared for the hour, month and year, they are waiting for the exact year, month, day and even hour, known only to God the Father, to make the invasion.
That these Four Angels who were bound at the river Euphrates, were bad angels is seen from the fact that they were bound, and that they are the leaders or commanders of an army of 200,000,000.

        This army of horsemen is a supernatural army. It is not made up of ordinary men and horses.

                The fact that these angels were bound at the Euphrates, where Satan's seat was in years past, and where it is to be again in the City of Babylon restored, and from where he will do his evil work, makes it clear that this army is a part of Satan's forces.
The Sixth Trumpet
Second Woe
The Plague of Horsemen.

"And the Sixth Angel sounded and I heard a voice from the Four Horns of the Golden Altar which is before God, saying to the sixth angel which had the trumpet, Loose the Four Angels which are bound in the great river Euphrates, and the Four Angels were loosed, which were prepared for an hour, and a day, and a month, and a year, for to slay the third part of men.
And the number of the army of the horsemen were two hundred thousand thousand: and I heard the number of them.
And thus I saw the horses in the Vision, and them that sat on them, having breastplates of fire, and of jacinth, and brimstone: and the heads of the horses were the heads of lions: and out of their mouth issued fire and smoke and brimstone.
By these three was the third part of men killed, by the fire, and by the smoke, and by the brimstone, which issued out of their mouths.
For their power is in their mouth, and in their tails: for their tails were like unto serpents, and had heads, and with them do hurt.
And the rest of the men which were not killed by these Plagues yet repent not of the works of their hands, that they should not worship devils, and idols of gold and silver, and brass, and stone, and of wood; which neither can see, or hear, nor walk: neither repented they of their murders, nor of their sorceries, nor of the fornication, nor of their thefts."
Before their face the people shall be much pained: all faces shall gather blackness.

          They shall run like mighty men; they shall climb the wall like men of war; and they shall march every one his ways, and they shall not break ranks; neither shall one trust another; they shall walk every one in his path; and when they fall upon the sword, they shall not be wounded.

                  They shall run to and fro in the city; they shall run upon the wall, they shall climb up upon the houses; they shall enter in at the windows like a thief.

                           The earth shall quake before them the heavens shall tremble; the sun and the moon shall be dark, and the stars shall withdraw their shining.   Joel 2:4-10

There are things in this prophecy that makes us doubt that an invasion of literal horsemen is not meant.

       Horses do not climb walls or climb up upon roofs or enter windows like a thief.

       These are spirit beings as demons, looking more like locusts but not literal locusts; but scorpion locusts that John described.
The description of Joel's prophecy is remarkable.

       He speaks of an army of horsemen, but which seems to refer to John's scorpion locusts, appear as horses and as horsemen, so shall they run like the noise of chariots; on the tops of mountains shall leap like the noise of a flame of fire that devours the stubble, as a strong people set in battle array.
The length of time is mentioned twice, and the character of the torment was like that which follows the sting of a scorpion, which causes excruciating pain that can cause the sufferer to want to die.

          Those tormented will seek death and shall not find it; and shall desire to die, but death shall flee from them.

                    This says that the locusts or demons controlling them will have power to prevent death.
We're not given the size of the locusts, but they were much larger than ordinary locusts.

          These locusts do not feed on vegetation like ordinary locusts, but were forbidden to hurt the grass or the trees or anything green.

                    They were to afflict only men and they had human intelligence because they afflicted only men who didn't have the seal of God in their foreheads. They were not permitted to kill, only torment for a limited time, five months.
The locusts that John saw come out of the Bottomless Pit were a kind of infernal cherubim.

         That is, they were a combination of the horse, the man, the woman, the lion, and the scorpion, and the sound of their wings in flying was the sound of chariots of many horses running to battle.
When the star angel opened the bottomless pit, smoke, like the smoke of a great furnace came out darkening the sun and there came out of the smoke locusts upon the earth.

          These were not ordinary locusts.
          Neither were they locusts of the eighth Egyptian plague.
The Bottomless Pit is not Hell or Hades, the place of abode of the Spirits of wicked men and women until the resurrection of the Wicked Dead.

            Neither is it Tartarus the Prison House of the fallen angels in Jude 6-7, nor the Lake of Fire, the final hell in Matthew 25:41.

            But it is the place for the demons, who are not Satan's angels but a group of disembodied spirits. They are wicked, unclean, vicious and have power to derange both mind and body.

                  They are Familiar Spirits and the Seducing Spirits that Paul warned Timothy about in 1 Timothy 4:1.
The work of both Angels is the same, to unlock and lock the bottom-less pit.

           It doesn't seem reasonable that God would entrust the Key of the Prison House of the demons to a Fallen Angel or even to Satan himself.
John said that he saw the descent of the star, or angel and it descended so rapidly that it appeared to be falling.

         This is the same Star Angel that comes down from heaven, having the key of the bottomless pit and a great chain in his hand, and binds Satan and casts him into the pit.

                 So it's clear that the star angel isn't Satan.
When the Fifth Trumpet sounded, John saw a star fall from heaven.
 
          That it was not a literal star is clear because the star in the next verse is spoken of as a person [He], in the Old Testament angels were called stars.

                  Because the star was fallen from heaven doesn't mean that it was a fallen angel, or Satan as some have thought.
Fifth Trumpet
First Woe
The Plague of Locusts
Revelation 9:1-12

"And the Fifth Angel sounded, and I saw a star fall from Heaven unto the earth: and to him was given the key to the bottomless pit.
And he opened the bottomless pit, and there arose a smoke out of the pit, as the smoke of a furnace; and the sun and the air were darkened by reason of the smoke of the pit.
And there came out of the smoke locusts upon the earth: and unto them was given power, as the scorpions of the earth have power.
And it was commanded them that they should not hurt the grass of the earth, neither any green thing, neither any tree; but only those men which have not the seal of God in their foreheads.
And to them it was given that they should not kill them, but that they should be tormented five months: and their torment was as the torment of a scorpion, when he striketh a man.
And in those days shall men seek death, and shall not find it: and shall desire to die, and death shall flee from them.
And the shape of the locusts were like unto horses prepared unto battle: and on their heads were as it were crowns of gold, and their faces were as the faces of men.
And they had hair as the hair of women, and their teeth were as the teeth of lions.
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.
And they had tails like unto scorpions, and there were stings in their tails: and their power was to hurt men five months.
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. One woe is past; and, behold, there come two woes more hereafter."



The Angel Warning
Three Woes Announced
Revelation 8:13

"And I beheld, and heard an angel flying through the midst of heaven, saying with a loud voice, woe, woe, woe, to the inhabiters of the earth by reason of the other voices of the Trumpet of the three angels, which are yet to sound."
What happens under the Fourth Trumpet is similar to what happened under the Sixth Seal.

          These are some of the Signs spoken of by Jesus in Luke's Gospel that precedes His Second Coming.

                     The signs in the Sun, and in the Moon, and in the Stars and upon the earth distress of nations with perplexity.
Never forget 911

Fourth Trumpet
Moon and Stars Smitten
Revelation 8:12

"And the Fourth Angel sounded and the third part of the Sun was smitten and the third part of the Moon and the third part of the Stars; so as the third part of them was darkened and the day shone not for a third part of it, and the night likewise."
Wormwood is an herb, very bitter and is used in the manufacture of Absinthe.

          It is used a lot in France as a beverage and is more intoxicating and destructive than ordinary liquors.

                 This is foretold by a Prophet named Jeremiah. "Therefore thus saith the Lord of Hosts, because they have forsaken my law, Behold, I will feed them, even this people (Israel)  with wormwood and give them water of gall to drink."
Jeremiah 9:13-15.
When the Third Trumpet sounded a great star fell from heaven burning like a lamp.
           
            This could be another meteor that will look like a torch on its path through the heavens and when its gaseous vapors are scattered as it explodes, they will be absorbed by the third part of the rivers and fountains of waters and be poisoned and made bitter and many men shall die from drinking the water.
Third Trumpet
The Star Wormwood
Revelation 8:10-11

"And the Third Angel sounded, and there fell a great star from heaven, burning as it were a lamp, and it fell upon the third part of the rivers, and upon the fountains of waters; and the name of the Star is Wormwood: and the third part of the waters (rivers) became wormwood, and many men died of the waters, because they were made bitter."
One third of the ships will be destroyed also, possibly by a tidal wave, or the meteor may fall on a fleet of navel vessels.
The only difference between the First Egyptian Plague and the effect on the Mediterranean Sea by the falling meteor into it at the sounding of the Second Trumpet, will be that only one third of the sea will become blood and only one third of the living creatures in the sea will die.
A Great Mountain is to fall on the sea, and the Judgments that pour from the Trumpets and Vials are to fall mainly on the part of the world bordering the Mediterranean Sea, and it's possible that the Sea mentioned is the Mediterranean Sea.

       John doesn't say that it was a Mountain that he saw cast into the sea, but that it appeared like a mountain, not a burning volcano, but a huge meteor mass ablaze with fire.

               That was as near as John could describe it. Its effect was to turn a third part of the sea into blood. Much like the Plague in Exodus 7:19,21.
Second Trumpet
The Burning Mountain
Revelation 8:8-9

"And the second Angel sounded, and as it were a Great Mountain burning with fire was cast into the sea: and the third part of the sea became blood; and the third part of the creatures which were in the sea, and had life, died; and the third part of the ships were destroyed."
In Egypt the hail smote every herb of the field and every tree, but in the First Trumpet only one-third of the trees and grass will be burnt up.
The difference between the Egyptian Plague and the one John describes is, that in Egypt man and beast suffered with the vegetation, with only the trees and the green grass suffering when the First Trumpet sounds, and the hail and fire will be mingled with blood.