In Rev 5 we see another multitude who praise the lamb and they note they were redeemed by the blood of the lamb out of every tribe tongue kindred and nation and note they will rule with him upon the earth. In Rev 6 we see 9 When He opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God and for the testimony which they held. 10 And they cried with a loud voice, saying, “How long, O Lord, holy and true, until You judge and avenge our blood on those who dwell on the earth?” 11 Then a white robe was given to each of them; and it was said to them that they should rest a little while longer, until both the number of their fellow servants and their brethren, who would be killed as they were, was completed. This group seems to be isolated from the group in Rev 5. The group is Rev 7 is specific to those who come out of the tribulation. They could be tribulation saints who die during the tribulation which Dan 7 and Rev 13 seem to indicate a very high number will be slain of the saints. Rev 13 He was granted power to give breath to the image of the beast, that the image of the beast should both speak and cause as many as would not worship the image of the beast to be killed.Dan 7
He shall speak pompous words against the Most High,
Shall persecute[fn] the saints of the Most High,
And shall intend to change times and law.
Then the saints shall be given into his hand
For a time and times and half a time.
26 ‘But the court shall be seated,
And they shall take away his dominion,
To consume and destroy it forever.
27 Then the kingdom and dominion,
And the greatness of the kingdoms under the whole heaven,
Shall be given to the people, the saints of the Most High.
His kingdom is an everlasting kingdom,
And all dominions shall serve and obey Him
Both of these prophecies have a 42 month duration of persecution. Both are stopped by the coming of the LORD. Rev 12 shows Satan thrown down out of heaven and his time is short. 10 Then I heard a loud voice saying in heaven, “Now salvation, and strength, and the kingdom of our God, and the power of His Christ have come, for the accuser of our brethren, who accused them before our God day and night, has been cast down. 11 And they overcame him by the blood of the Lamb and by the word of their testimony, and they did not love their lives to the death. 12 Therefore rejoice, O heavens, and you who dwell in them! Woe to the inhabitants of the earth and the sea! For the devil has come down to you, having great wrath, because he knows that he has a short time.”
This group in Rev 7 is likely those overcomer's described here who by the word of their testimony did not love their lives unto death. Many are saved in the day of wrath. Jesus in Isaiah 61 spoke of the acceptable year of the LORD and the day of vengeance of our God. Much is accomplished in this period.