Revelation 12:17 (NASB95)
17So the dragon was enraged with the woman, and went off to make war with the rest of her children, who keep the commandments of God and hold to the testimony of Jesus.
Revelation 13:5–10 (NASB95)
5There was given to him a mouth speaking arrogant words and blasphemies, and authority to act
for forty-two months was given to him.
6And he opened his mouth in blasphemies against God, to blaspheme His name and His tabernacle, that is, those who dwell in heaven.
7It was also given to him to make war with the saints and to overcome them, and authority over every tribe and people and tongue and nation was given to him.
8All who dwell on the earth will worship him, everyone whose name has not been written from the foundation of the world in the book of life of the Lamb who has been slain.
9If anyone has an ear, let him hear.
10If anyone is destined for captivity, to captivity he goes; if anyone kills with the sword, with the sword he must be killed.
Here is the perseverance and the faith of the saints.
Revelation 3:10 (NASB95)
10‘
Because you have kept the word of My perseverance, I also will keep you from the hour of testing, that hour which is about to come upon the whole world, to test those who dwell on the earth.
Christians (the one people who refuse the mark of the beast) will be killed, hunted down and executed in a time when hiding will be the most difficult in history (technologies and the fact that no one can buy or sell without the mark). It's practical purpose (the mark of the beast) is to expose and track down Christians.
At any rate, the few Christians who survive to the near end of 3 1/2 years will be raptured out but they will be so far underground in hiding they will not be missed. In fact, IMHO, the reason the beast goes ahead with his ascent to the throne of the mercy seat in the holiest place in the temple 105 days before the rapture is because by all appearances the Church has already been exterminated.
The Bible says that the believers will be kept from the plagues to follow. It does not say how they will be. Noah and family were kept from the flood physically yet returned to the world afterward. Enoch and Elijah were translated from this world apparently into spirit since no man has yet ascended into heaven save Jesus (John 3:3). My guess (and that's all it is) is they were translated into spirit to what came to be known as Abraham's Bosom in sheol until the Spirit of Jesus (God the Word) took them to heaven post crucifixion (Ephesians 4:8-10).
Here's another of my charts.