they will reign upon the earth

The four living creatures and the twenty-four elders are referring to Revelation 20, the only account of human beings reigning on earth, as a "kingdom and priests to God." Observe carefully in Revelation 20 that those who reign with Jesus Christ for 1000 years are those who are of the first resurrection, namely those Believers who died for their faith during the Great Tribulation.

Then I saw thrones, and they sat on them, and judgment was given to them. And I saw the souls of those who had been beheaded because of their testimony of Jesus and because of the word of God, and those who had not worshiped the beast or his image, and had not received the mark on their foreheads and on their hands; and they came to life and reigned with Christ for a thousand years. The rest of the dead did not come to life until the thousand years were completed. This is the first resurrection. Blessed and holy is the one who has a part in the first resurrection; over these the second death has no power, but they will be priests of God and of Christ, and will reign with Him for a thousand years. (Rev 20:4-6)

There is no mention that Believers, who died of natural causes or for any other reason, are part of this reigning class.

From Revelation: An Explication © A resource for learning how to read the Bible.