Antichrist, as the seventh Caesar of the Roman Empire, will be killed and resurrected with the spirit (from the abyss) of Nero, the fifth Caesar of the Roman Empire, to be the eighth Caesar of the Roman Empire (Rev. 17:8, 10-11; 13:3). Revelation 17:8a says, "The beast whom you saw was, and is not, and is about to come up out of the abyss and go into destruction." The beast, who is Antichrist, "was" in the person of Caesar Nero before John wrote Revelation. He "is not" at the time of John's writing, because Nero died by that time. He "is about to come up out of the abyss." This implies that Nero's spirit is now in the abyss and is about to emerge from it to take possession of the body of the slain and resurrected Antichrist, as indicated in Revelation 13:3.
Revelation 17:10 says, "And are seven kings: five have fallen, one is, the other has not yet come; and when he comes, he must remain a little while." The seven kings are the seven Caesars of the Roman Empire. The first five have fallen, that is, they have died unnaturally (Judg. 3:25; 2 Sam. 1:10, 25, 27). They are Julius Caesar, Tiberius, Caligula, Claudius, and Nero, all of whom either were murdered or committed suicide before John wrote Revelation. The sixth one, Domitian, who was also murdered, was living when Revelation was written; therefore, it was said of him that he "is." The "other," the seventh, who will be Antichrist, had "not yet come" at that time. "When he comes, he must remain a little while," and he will be slain and resurrected with the spirit of the fifth, who is Nero, to be the eighth.
Revelation 17:11 says, "And the beast who was, and is not, he also is the eighth, and is of the seven, and goes into destruction." Antichrist will be the coming seventh Caesar. But he "also is the eighth." According to Revelation 13:3, Antichrist will be slain and resurrected. In that resurrection, the spirit of Nero (the fifth Caesar), which comes up out of the abyss, will animate the dead body of the seventh Caesar, Antichrist. This one, composed of the fifth and seventh Caesars, is the eighth. Hence, he "is of the seven." It is no wonder that people marvel at the sight of such an extraordinary being (Rev. 17:8). Revelation 13:3 says that when Antichrist is resurrected from death, the whole earth marvels after him.
We know that the spirit of the coming Antichrist is the spirit of Caesar Nero because of Revelation 13:18—"Here is wisdom. Let him who has understanding calculate the number of the beast, for it is the number of a man; and his number is six hundred and sixty-six." The number represented by the letters of the name Caesar Nero in Hebrew is six hundred sixty-six. By this we know that the eighth Caesar, the coming Antichrist, the beast, will have the spirit of Caesar Nero.
Another item which has been made more firm by the New Testament prophecies is the location of Armageddon (Rev. 16:16).
Armageddon, in Hebrew, means Mount Megiddo, which means the mount of slaughter.
Megiddo is located west of the river Jordan, close to the Mediterranean Sea, between Samaria and Galilee (Judg. 5:19; 2 Kings 23:29; Zech. 12:11).