In Rev 9:11, the Bible states that the king of the Locusts is Abaddon / Apollyon. Abaddon / Apollyon is the Hebrew and Greek name for the destroyer. But, who does this represent? Also, this king is also called the angel of the Bottomless Pit. Please consider viewing the You Tube video at the link below to lean more about this important topic. Or, consider viewing the associated study notes on the Revelation 8-10 study notes page on this website.
