In Revelation 12, in the war that breaks out in heaven, there's no mention of a weapon which actually overcomes the devil so as to be cast out of heaven and onto the earth, other than the ''blood of the lamb'' mentioned in verse 11.
Neither are there any other warrying parties mentioned in between verses 9 and 11 besides Michael's and his host against the Devil and his, and in which verses the defeated is the same Devil by the war which he fought against Michael to his defeat.
7 And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,
8 And prevailed not; neither was their place found any more in heaven.
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.
10 And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night.
11 And they overcame him because of the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death.
12 Therefore rejoice, [ye] heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time.
Moreover, the rejoicing is urged upon those that dwell in heaven, the place from which the devil is cast out.
But put the case that the pronoun they in verse 11 refer to saints, then it would be an assumption which places them in heaven and not on earth, because rejoicing is in heaven and it's because of the casting out of the devil one, While woes are for the earth dwellers.
In addition experts say the conquering/overcoming is because of that blood, which differs from conquering/overcoming by that blood as many versions have it.
So, how is the devil defeated by Michael and His messengers because the ''blood of the Lamb,'' or by it, if you insist?