Well yes, believers are supposed to accept and believe what is in their bible, but all that is has already happened. Nothing new will come out of that foolish book.
The next time Jesus comes back will be in the air to receive those who trust Him into Heaven with Him.
After that (7 years later), He will come back "with" His saints to earth. At that time, He will set up His Kingdom on earth for 1000 years.
It won't be until that time period is over that the things in Rev. 14:20 takes place.
So, in answer to your question, when Jesus returns to this earth, He will set up His Kingdom and reign on earth for 1000 years. The Bible does say that He will reign with an iron rod. In other words, He is not going to be like our politicians and other political leaders. Nobody is going to push Him around.
yes, millions of people will be killed. the reason is because the people who didn't believe in him will have chosen satan over him by that time. right now we're in a time where Jesus has in so many words said "if you're not with me, you're against me. if you're not in the light, you're in the dark." but there will be no ambiguous darkness of not knowing whose side you're on by the time the end of the world comes around, because the antichrist will have forced people to take sides anyway. perhaps you also read the whole mark of the beast thing people talk about?
yeah, that, so then, people are going to be at war with christians, who will be on the run. it's already like this now in some places, but this will be a time of widescale, worldwide chaos- a time in which christians everywhere indiscriminately will be murdered for not accepting the mark and knowingly choosing satan over jesus. it can be said that if you're in satan, you've surrendered to the darkness, and for that reason, since God "is light and in him is no darkness", he must extinguish the remaining dark, or, all those millions of people you referenced. God is the ultimate cleanser, purifier. he will have given the millions the chance to choose him over the world, and in the face of either fear or disbelief they will have turned against him, forsaken him, just as they did when he walked the earth. amazing how history repeats itself, isn't it?
He's here already and quickly working on destroying at least the United States. After that, who knows who's next! The thugs of the world will make quick work of this place, the earth will be one huge parking lot.
As usual, the question is incorrect; Jesus returns much before the passage quoted (see Revelation 14:1 - that is His appearance). The passage you refer to is Armageddon, or more correctly, the battle at Armageddo.