Grammatically, the antecedent of the pronoun “he” in Daniel 9:27 is the compound noun “the prince that shall come”, Satan.
Daniel 9:27 reads “he” shall confirm a covenant with many for 1 week, or 1 seven, meaning 7 years. And then in the midst of the week, “he” shall cause the sacrifice and oblation to cease.
“And after threescore and two weeks shall Messiah be cut off, but not for himself: and the people of the prince that shall come shall destroy the city and the sanctuary; and the end thereof shall be with a flood, and unto the end of the war desolations are determined. And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make it desolate, even until the consummation, and that determined shall be poured upon the desolate.”
– Daniel 9:26-27
The antecedent of “he” cannot be “Messiah”, because it would not make sense for the Messiah to stop the oblation.
And moreover, the antecedent of “he” cannot be “the people of the prince that shall come”, because that would be grammatically wrong. One is singular, and the other is plural. By the way, “the people of the prince that shall come” that “shall destroy the city and the sanctuary” in Daniel 9:26 are the Romans, circa 70 AD.
Therefore, the antecedent of “he” must be the prince that shall come. A “prince” is biblical nomenclature for an angel. For example, Daniel 12:1 speaks of Michael, the “great prince”.
From Daniel 11:31, it is clear that the oblation will be stopped by the Antichrist, or more specifically by an army of the Antichrist.
“And arms shall stand on his part, and they shall pollute the sanctuary of strength, and shall take away the daily sacrifice, and they shall place the abomination that maketh desolate.”
– Daniel 11:31
But Daniel 8:9-12 goes further and explains that ultimately it will be the spirit that will possess the Antichrist, i.e. Satan, that will stop the oblation.
“And out of one of them came forth a little horn, which waxed exceeding great, toward the south, and toward the east, and toward the pleasant land. And it waxed great, even to the host of heaven; and it cast down some of the host and of the stars to the ground, and stamped upon them. Yea, he magnified himself even to the prince of the host, and by him the daily sacrifice was taken away, and the place of his sanctuary was cast down. And an host was given him against the daily sacrifice by reason of transgression, and it cast down the truth to the ground; and it practised, and prospered.”
– Daniel 8:9-12
Daniel 8:9-12 says, the Little Horn will wax great towards the host of heaven, and he will cast some of the host to the ground, and he will even magnify himself against the prince of the host. Surely this is Revelation 12:7-12, the war in heaven that precedes the 7 year tribulation.
“And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels, And prevailed not; neither was their place found any more in heaven. 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. 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. And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death. 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.
– Revelation 12:7-12
Many people think that Satan was cast out of heaven in the distant past, well before the birth and crucifixion of Jesus Christ. This is wrong. Revelation 12:7-12 explains that Satan is cast out at the beginning of the 7 years. Thus, at the time Messiah is cut off, in Daniel 9:27, Satan the prince, strictly speaking, has not yet come.
So, the antecedent of “he” who confirms and breaks the covenant with many must be “the prince that shall come”. This is the reason why the covenant with many of Daniel 9:27 can be confirmed by the king of Babylon and subsequently broken by the Antichrist.