“And they had a king ouer them, which is the Angel of the bottomlesse pit, whose name in the Hebrew tongue is Abaddon, but in the Greeke tongue hath his name Apollyon.”
1611 King James Version (KJV)
9:11 And they have over them a king - One by whom they are peculiarly directed and governed. His name is Abaddon - Both this and Apollyon signify a destroyer. By this he is distinguished from the dragon, whose proper name is Satan.
Re 9:11 They had a king over them. The real king was not the star, but the power of the bottomless pit. Apollyon. The destroyer; either the devil or one of his angels.