What is the Death Toll in Revelation? Will There be Zombies?

(About 8 billion on earth now)

2nd seal is a sword (Tribulation)
1/3 by fire (on Day of Wrath)
1/4 die 4 ways (after 4th kingdom arrives: Great Tribulation)
Lamb kills army by sword (after Great Tribulation)

There are times of ingathering. These appear as the host with the Lamb.
(We didn't even count rev 14:20 where blood rises to horses bridles with first trampling of winepress at close of Day of Wrath)

You could easily conclude all the thirds of earth die with a few strands of 'hairs' making it to preservation.

Is 13:12
I will make man scarcer than pure gold, and mankind rarer than the gold of Ophir. 13Therefore I will make the heavens tremble, and the earth will be shaken from its place at the wrath of the LORD of Hosts on the day of His burning anger.

Will There be Zombies?
The abyss gets opened and all come out of their graves:

John 5:28
...the hour is coming when all who are in their graves will hear His voice 29and come out—those who have done good to the resurrection of life, and those who have done evil to the resurrection of judgment

Then anyone who worships the beast gets cast into the place where people can't die but are tormented. (a dead soul is one without a body) This is Gei-Hinnom.