Parallel
Revelation 9:15
Nestle 1904 Greek New Testament · Berean Standard Bible
καὶ ἐλύθησαν οἱ τέσσαρες ἄγγελοι οἱ ἡτοιμασμένοι εἰς τὴν ὥραν καὶ ἡμέραν καὶ μῆνα καὶ ἐνιαυτόν ἵνα ἀποκτείνωσιν τὸ τρίτον τῶν ἀνθρώπων
So the four angels who had been prepared for this hour and day and month and year were released to kill a third of mankind.