Thanks, Amy. While the Catholic Church recognizes a form of rapture, it's a much bigger deal for Fundamentalists and some Evangelicals. They believe they will be carried up to heaven immediately before Christ's return. Then there is a literal 1000 years with Christ reigning on earth, followed by the rise of the Antichrist & False Prophet, the unleashing of Satan, a few years of chaos, Jesus killing whoever he needs to, then final judgment. I may have some of the timeline wrong, but they believe they will not need to suffer the Great Tribulation because they won't be here.
EDIT: The Bible and Catholic Church don't use the term rapture at all. I Thessalonians 4:16-17 says this: We who are alive and remain shall be caught up, shall be caught up together with them in the clouds. This is as close as Scripture gets to anything representing the rapture. It was meant to console early Christians that they would be reunited with loved ones.
I was looking for a title that might appeal to both thriller readers and Christians, like the "Exorcist". I've settled on The Unholy Trinity Unleashed for the time being. I wanted Satan's Last Stand, but K and Seabrass have me convinced for now not to give away the ending. I don't really, since it doesn't mean all three antagonists die, just that Satan knows he's supposed to die, so he sets events in motion that attempt to change the final outcome.
My biggest headache right now is that the (best) Catholic study guide that I selected as the basis for end time events says to treat key end time events as allegory, like the battle at Armageddon (Mount Megiddo). I wasn't planning to have an actual battle, since that's another Protestant belief, but Revelation makes pretty clear that Jesus/The Father literally destroy the enemies of God. The book says Jesus personally destroys the Antichrist's armies with a sword that comes out of His mouth. The study guide says that's a reference to Christ's holy words, which I agree with, but then the guide doesn't explain how that's supposed to happen. Is His preaching so powerful that all evildoers just drop dead at hearing it? If so, why was there no such power displayed in the Gospels?