They had as king over them the angel of the Abyss, whose name in Hebrew is Abaddon and in Greek is Apollyon (that is, Destroyer). Apocalypse 9:11 (NIV) ✝
They have as king over them the angel of the bottomless pit. His name in Hebrew is Abaddon, and in Greek he is called Apollyon. The first woe has passed; behold, two woes are still to come. - Revelation 9:11-12 (ESV)