Again, the prophetic scriptures do not describe the Pope and the RCC
The mark that you speak of is one that will be taken by those who want to identify with Satan's beast .... his name is Abaddon and his mark is 666 .... Abbadon is clearly not the Pope
Revelation
14:9 And the third angel followed them, saying with a loud voice, If any man worship the beast and his image, and receive his mark in his forehead, or in his hand,
14:10 The same shall drink of the wine of the wrath of God, which is poured out without mixture into the cup of his indignation; and he shall be tormented with fire and brimstone in the presence of the holy angels, and in the presence of the Lamb:
14:11 And the smoke of their torment ascendeth up for ever and ever: and they have no rest day nor night, who worship the beast and his image, and whosoever receiveth the mark of his name.
And if you are a true believer living at the time, you will not be on the earth when Abaddon is released from the abyss .... but you will observe the tribulation from heaven