They have as king over them the angel of the abyss, whose name in Hebrew is Abaddon, and in Greek, Apollyon. ¹ 

Then ¹  I saw an angel descending from heaven, holding ²  in his hand the key to the abyss and a huge chain.

Then ¹  the fifth angel blew his trumpet, and I saw a star that had fallen from the sky ²  to the earth, and he was given the key to the shaft of the abyss. ³ 

He ¹  opened the shaft of the abyss and smoke rose out of it ²  like smoke from a giant furnace. The ³  sun and the air were darkened with smoke from the shaft.

When ¹  they have completed their testimony, the beast that comes up from the abyss will make war on them and conquer ²  them and kill them.

The beast you saw was, and is not, but is about to come up from the abyss ¹  and then go to destruction. The ²  inhabitants of the earth – all those whose names have not been written in the book of life since the foundation of the world – will be astounded when they see that ³  the beast was, and is not, but is to come.