In studying the traditional Jewish viewpoints, we find that in the Talmud, it is stated that there are seven names for Ghenna (what we call Hell). These are: Sheol, Abaddon or Destruction, Corruption, Horrible Pit, Miry Clay, Shadow of Death and the Nether world. It is also stated that Gehenna has "seven stories", or levels, which are named as: Sheol, Abaddon, Shadow of Death, Nether world, Land of Forgetfulness, Gehinnom, and Silence.
Furthermore, it is said that Gehenna has three entrances: one in the wilderness, one in the sea and one in the Valley of Hinnom in Jerusalem. We find, in the Book of Revelation, that the Beast or Antichrist, who ascends out of the pit, does in fact, appear at those three locations (Rev. 11:7-8; 13:1; 17:3).
Here in verse 11 of the 9th chapter, we find an angel, named Abaddon, as king of the abyss. To properly identity him and keep this verse in proper context, we have to go back to verse 1, where we find the star (angel), who had been given the key, with which he opens the abyss. Thus, we can understand that he who opens the pit and frees its captives, is set as king over them, and received as a sort of Messiah. It's reminiscent of Jesus descending to Paradise, after His death, and leading forth those who had been waiting for Him there.
When we get to Rev. 11:7, we find the first mention in the Book of Revelation of the beast (antichrist); and we see him ascending out of the abyss and killing the two witnesses of God. As stated earlier, the abyss is not a place of human captivity. Therefore, we can understand that it is the angel, Abaddon, who is the one spoken of there. He will make war with, and prevail against the two witnesses.
In chapter 22:16, Jesus likened Himself to, "...the Bright and Morning Star..." The star whose presence continues at the dawn of the day, when all others have faded out of sight. So, in bringing forth the great deception, the star (angelic being) which fell from heaven (9:1) will seek to emulate or copy the One who says He is "the Bright and Morning Star".
"And because they did not receive the love of the truth that they might be saved.... God will send them strong delusion, that they should believe the lie." (II Thess. 2:10-11).
Th traditional or prevailing viewpoint in the Church is that the antichrist will be a human who is posessed by Satan. Here however, we are seeing something quite different. In chapter 9, we see Abaddon's fall to the earth, followed by his opening of the abyss. At some point following this, he will be dealt a death blow which will hurl him into the pit which he had opened. Shortly afterwards however, he will ascend out of the pit (Rev.13:1) and make war with, and prevail against, the two witnesses at Jerusalem (11:7). He will then enter the newly built temple, set up an image of himself, and proclaim himself to be God.