Blood
“And in her was found the blood of prophets, and of saints, and of all that were slain upon the earth.” (Rev. 18:24 KJV)
God has gotten vengeance on Babylon for His people. He has avenged the blood of those that were martyred and suffered persecution.
“And they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth?” (Rev. 6:10 KJV)
“And the nations were angry, and thy wrath is come, and the time of the dead, that they should be judged, and that thou shouldest give reward unto thy servants the prophets, and to the saints, and them that fear thy name, small and great; and shouldest destroy them which destroy the earth.” (Rev. 11:18 KJV)
“For they have shed the blood of saints and prophets, and thou hast given them blood to drink; for they are worthy.” (Rev. 16:6 KJV)
“And I saw the woman drunken with the blood of the saints, and with the blood of the martyrs of Jesus: and when I saw her, I wondered with great admiration.” (Rev. 17:6 KJV)