The idea of the false prophet is difficult for many to understand. It is actually just another 'role' that Satan will play. Satan will be the 1) beast king, and 2) false prophet, and 3) the dragon, all rolled into one. How is this proven? Easy.
1. The beast and false prophet also work the miracles that the dragon does:
Rev 16:13-14
13 And I saw three unclean spirits like frogs come out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet.
14 For they are the spirits of devils, working miracles, which go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty.
KJV
2. The one speaking as a dragon is shown working those miracles in Rev.13 and is called the "another beast". Some even call this "another beast" the false prophet when that term is nowhere to be found there in Rev.13. They natural equate this "another beast" with the false prophet simply because of the working of these miracles linked to the Rev.16 verses above.
Rev 13:13-14
13 And he doeth great wonders, so that he maketh fire come down from heaven on the earth in the sight of men,
14 And deceiveth them that dwell on the earth by the means of those miracles which he had power to do in the sight of the beast; saying to them that dwell on the earth, that they should make an image to the beast, which had the wound by a sword, and did live.
KJV
The beast and false prophet are destroyed in the lake of fire when Jesus comes, but the dragon is not destroyed yet then.
Rev 19:20
20 And the beast was taken, and with him the false prophet that wrought miracles before him, with which he deceived them that had received the mark of the beast, and them that worshipped his image. These both were cast alive into a lake of fire burning with brimstone.
KJV
This destruction of the beast and false prophet at Jesus' coming is very important to note, because no flesh born man is cast into the "lake of fire" at Jesus' coming. The wicked are cast into the "lake of fire" at God's GWT Judgment after Christ's 1,000 years reign with His elect. Until that future time, NO FLESH BORN MAN is judged to perish in that future lake of fire. It's that simple.
But there in Rev.19 we are shown the beast and false prophet being destroyed at Christ's coming, but not the dragon (Satan). That means the beast (king role) and false prophet, represent ROLES that Satan will play as the Antichrist. Those two roles of course are destroyed at Christ's coming.