Revelation 9:11

and they have over them a king -- the messenger of the abyss -- a name is to him in Hebrew, Abaddon, and in the Greek he hath a name, Apollyon.

Ephesians 2:2

in which once ye did walk according to the age of this world, according to the ruler of the authority of the air, of the spirit that is now working in the sons of disobedience,

Job 26:6

Naked is Sheol over-against Him, And there is no covering to destruction.

John 8:44

Ye are of a father -- the devil, and the desires of your father ye will to do; he was a man-slayer from the beginning, and in the truth he hath not stood, because there is no truth in him; when one may speak the falsehood, of his own he speaketh, because he is a liar -- also his father.

John 12:31

now is a judgment of this world, now shall the ruler of this world be cast forth;

John 14:30

I will no more talk much with you, for the ruler of this world doth come, and in me he hath nothing;

John 16:11

and concerning judgment, because the ruler of this world hath been judged.

2 Corinthians 4:4

in whom the god of this age did blind the minds of the unbelieving, that there doth not shine forth to them the enlightening of the good news of the glory of the Christ, who is the image of God;

1 John 4:4

Ye -- of God ye are, little children, and ye have overcome them; because greater is He who is in you, than he who is in the world.

1 John 5:19

we have known that of God we are, and the whole world in the evil doth lie;

Revelation 9:1-2

And the fifth messenger did sound, and I saw a star out of the heaven having fallen to the earth, and there was given to it the key of the pit of the abyss,

Revelation 12:9

and the great dragon was cast forth -- the old serpent, who is called 'Devil,' and 'the Adversary,' who is leading astray the whole world -- he was cast forth to the earth, and his messengers were cast forth with him.

Treasury of Scripture Knowledge

Summary

And they had a king over them, which is the angel of the bottomless pit, whose name in the Hebrew tongue is Abaddon, but in the Greek tongue hath his name Apollyon.

The angel

Abaddon

Bible References

They had

Revelation 12:9
and the great dragon was cast forth -- the old serpent, who is called 'Devil,' and 'the Adversary,' who is leading astray the whole world -- he was cast forth to the earth, and his messengers were cast forth with him.
John 12:31
now is a judgment of this world, now shall the ruler of this world be cast forth;
John 14:30
I will no more talk much with you, for the ruler of this world doth come, and in me he hath nothing;
John 16:11
and concerning judgment, because the ruler of this world hath been judged.
2 Corinthians 4:4
in whom the god of this age did blind the minds of the unbelieving, that there doth not shine forth to them the enlightening of the good news of the glory of the Christ, who is the image of God;
Ephesians 2:2
in which once ye did walk according to the age of this world, according to the ruler of the authority of the air, of the spirit that is now working in the sons of disobedience,
1 John 4:4
Ye -- of God ye are, little children, and ye have overcome them; because greater is He who is in you, than he who is in the world.
1 John 5:19
we have known that of God we are, and the whole world in the evil doth lie;

The angel

Revelation 9:1
And the fifth messenger did sound, and I saw a star out of the heaven having fallen to the earth, and there was given to it the key of the pit of the abyss,

Abaddon

John 8:44
Ye are of a father -- the devil, and the desires of your father ye will to do; he was a man-slayer from the beginning, and in the truth he hath not stood, because there is no truth in him; when one may speak the falsehood, of his own he speaketh, because he is a liar -- also his father.