Revelation 9:1-2; Revelation 9:11
The fifth angel sounded his trumpet, and I saw a star that had fallen from the sky to the earth. The star was given the key to the shaft of the Abyss.
When he opened the Abyss, smoke rose from it like the smoke from a gigantic furnace. The sun and sky were darkened by the smoke from the Abyss.
They had as king over them the angel of the Abyss, whose name in Hebrew is Abaddon, and in Greek, Apollyon.