In your 5/05/2024 post How, after 15 times does the meaning change at the end? (fivedoves.com) you asked the following question regarding the meaning of east being changed from east of Israel in the Middle East to the Far East where China, Vietnam & North Korea are located:

But then, suddenly, in the last book, in chapter 16, why do people say that kings of the east then must be referring to China, Vietnam, North Korea, etc?

Revelation 16:12 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.

In Rev. 9:14-15 when the 6th trumpet is sounded by the angel, 4 angels bound in the great river Euphrates are loosed to slay the third part of men, and in Rev. 9:16 there is an army of 200 million horsemen who also help kill the third part of men. This was somehow tied in with Rev. 16:12 with the 6th angel pouring out his vial on the great river Euphrates drying up the waters so the way of the kings of the east might be prepared. Because China now has a population of 1.41 billion people, that is where some theologian thought the 200 million horsemen would come from.  However, the 200 million horsemen could come from a combination of armies of different countries in the Middle East that are east of Israel.