The end time Beast will have ZERO to do with the RCC. It all happens after the Rapture anyway, thus anyone not taken will understand these "RCC Leaders" were chumps themselves. People who put forth the RCC idea and/or even the Islamic Idea just do not understand prophecy. The Beast was/will be a Gentile Government who dominates the Mediterranean Sea Region whilst Israel are an entity living in the land.
Thus this MAN whom Europe (10 as COMPLETE Europe) give their power unto in Rev. 17:12, will then turn around and name ANOTHER Beast (Man with Dominion/POWER) t rule over ALL Peoples Faith/Religion Choices as in you Chose to Worship the First Beast or else you die !!
Revelation 13:11 And I beheld another beast coming up out of the earth(Earth/Land = Israel); and he had two horns like a lamb (who is the highest Religious Leader in Israel? The High Priest), and he spake as a dragon(He is not of God thus he is of Satan). 12 And he exerciseth all the power of the first beast before him, and causeth the earth and them which dwell therein to worship the first beast, whose deadly wound was healed. 13 And he doeth great wonders, so that he maketh fire come down from heaven on the earth in the sight of men,
14 And deceiveth them that dwell on the earth by the means of those miracles which he had power to do in the sight of the beast; saying to them that dwell on the earth, that they should make an image to the beast, which had the wound by a sword, and did live. 15 And he had power to give life unto the image of the beast, that the image of the beast should both speak, and cause that as many as would not worship the image of the beast should be killed.
So, the Second Beast arises from THE LAND, not the Sea of Gentiles, he's a Jewish High Priest, we know Satan loves to defile what God put forth as holy, and the High Priest would come into the holy of hollies and splatter the blood of the sacrifice on the presence of the Lord. Just like Antiochus Epiphanes, this end time Beast will appoint a Jewish High priest who will then be given ALL POWER over ALL Religions and he will mandate Beast worship or death.
We can see the groundwork for this in Rev. 17:16, where no one in these Harlot Religions are allowed to live on, the Harlot is thus KILLED-OFF by the 10 kings (Europe) in league with these 2 Beast Powers over Government and Religion, thus Scarlet and Purple now make perfect sense, these two colors/dyes (google it) were very, very, very, very expensive to make, thus the Royals & Religious Orders of all religions wore these two colors, so when God cites the "Harlot" as having on or being dressed in Purple and Gold, He is saying that she represents ALL Harlot False Religions of All time, and she also represents False Governance, God is our only true governance, any other Government is doom to fail in reality, because mankind is evil in heart.
So, look for ONE MAN whom Europe allows to consolidate power unto himself, he will go forth conquering Israel and ALL of the Mediterranean Sea Region, then he will appoint a Jewish High Priest over WORLD RELIGIOJN, and the 2nd Beast will mandate the Worship of the First Beast. A simpler way to grasp this is DOMIION = Power thus that Beast was an Animalistic like power over a TERRITORY so to speak. So, lets drop this jargon and say what's going to really happen.
This MAN with the E.U.'s backing will conquer Israel and all of her immediate neighbors AND all of North Africa. He will them appoint the Jewish High Priest as his "Religious Tsar" of the whole area, so to speak and he will then give this ONE MAN all power over all men via Religion and this Religious Tsar will mandate Anti-Christ Worship or DEATH. It is literally that simple.