Revelations 16:12(kjv)
12 And the sixth angel poured out his vial upon the great river Euphrates; and the water thereof was dried up, that the way of the kings of the east might be prepared.
What I'm trying to show you(honest onlookers that don't realise who you really are) is how to extract info that is usually overlooked. We could assume that when this verse speaks of the Euphrates river and the kings of the East must also be talking of about the land on the west side of that river. Just to throw a spanner into the works I have heard somewhere that the Ephrates river doesn't flow the same as it use to, unsure why. What ever the reason who are the kings of the East? I hope this song helps you realise the answer
https://m.youtube.com/watch?v=LXxRtIP59qQ