Think I’ll stay away from a theoretical exposition but these passages might be what you’re looking for; (he who letteth) some say it’s the HS being the restrainer, but I tend to think it is Michael.
(1Jo 2:18) Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.
(2Th 2:7) For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way.
(2Th 2:8) And then shall that Wicked be revealed, whom the Lord shall consume with the spirit of his mouth, and shall destroy with the brightness of his coming:
(2Th 2:9) Even him, whose coming is after the working of Satan with all power and signs and lying wonders,
(Rev 12:7) And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,
(Rev 12:8) And prevailed not; neither was their place found any more in heaven.
(Rev 12:9) And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
It might depend who one thinks this angel is, chain in hand.
(Rev 20:1) And I saw an angel come down from heaven, having the key of the bottomless pit and a great chain in his hand.
(Rev 20:2) And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a thousand years,
(Rev 20:3) And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season.
(Dan 12:1) And at that time shall Michael stand up, the great prince which standeth for the children of thy people: and there shall be a time of trouble, such as never was since there was a nation even to that same time: and at that time thy people shall be delivered, every one that shall be found written in the book.