It has always been Satan with the beginning of his fall when pride was found in him when God placed him in the garden of Eden before the creation of man and is now the evil principality of the air. Isaiah 14:12-15 and Ezekiel 28:11-19 are dual references to Satan who was once God's special cherub (angel), but now known as the prince of the power of the air, 2 Corinthians 4:4; Ephesians 2:1-3, seeking in whom he can devour.
Rev 13 the beast rises up out of the sea as the sea here is symbolic of people and nations as in a sea of humanity, Daniel Chapter 7:1-8; Revelation 17:15. This beast is a Luciferian system that controls world wide economics, political, military, educational, environmental and false religious system that Satan works through. We have to remember that Satan is a created spirit and can only work through those of disobedience to God. This beast system that Satan works through gives its power to the beast out of the earth as the beast out of the earth appears as the Lamb of God, but is a false Christ being the son of perdition and last antichrist in the end of days, 2 Thessalonians 2:3-12.
Satan started his deception working through Nimrod who was the first king of Babylon. From that time forth he has worked through all the leaders of the four Empires throughout history and will continue with the leadership of the revived Roman Empire that has always persecuted God's own as even now works in disguise setting up the New World Order.
The remains of Babylon is known today as Hillah, Babil Governorate, Iraq about 53 miles from Bagdad.