Who is the god of this world mentioned in 2nd Corinthians 4:4?

The reason this question is particularly timely is because some of the things that have been recorded in the Bible that were accurate when spoken and written and subsequently translated have now already transpired or have expired, thus rendering them invalid as in respect to our current day.  This may indeed be the consideration in why this question has been asked.

The timing of the writing of the verse in question is the same as the entire New Testament: after the death, burial and resurrection of Jesus Christ and before the destruction of the temple in Jerusalem.

The passage being referred to in the question is printed below.   

2 Cor. 4:4

[1] Therefore seeing we have this ministry, as we have received mercy, we faint not;
[2] But have renounced the hidden things of dishonesty, not walking in craftiness, nor handling the word of God deceitfully; but by manifestation of the truth commending ourselves to every man's conscience in the sight of God.
[3] But if our gospel be hid, it is hid to them that are lost:
[4] In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them.

Tap on the link below to open the passage from the ekjv.org website.

• https://www.ekjv.org/2_corinthians.php#SecondCor4

The resurrection and Second Coming of Jesus Christ has changed some important things.

Jesus spoiled the principalities and powers through His voluntary and sacrificial death on the cross and His resurrection to life.

Spoil here does not refer to something rotting, it refers to spoils as in The Spoils of War.

Col. 2:6-15

[6] As ye have therefore received Christ Jesus the Lord, so walk ye in him:
[7] Rooted and built up in him, and stablished in the faith, as ye have been taught, abounding therein with thanksgiving.
[8] Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ.
[9] For in him dwelleth all the fulness of the Godhead bodily.
[10] And ye are complete in him, which is the head of all principality and power:
[11] In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ:
[12] Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead.
[13] And you, being dead in your sins and the uncircumcision of your flesh, hath he quickened together with him, having forgiven you all trespasses;
[14] Blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross;
[15] And having spoiled principalities and powers, he made a shew of them openly, triumphing over them in it.

What did Jesus take from them?

He took their power.  He did not take their positions. Principalities and powers still have positions, but they have no authority.  They only have the influence that they can achieve through deception.

The last enemy to be destroyed is death.

1 Cor. 15:22-28

[22] For as in Adam all die, even so in Christ shall all be made alive.
[23] But every man in his own order: Christ the firstfruits; afterward they that are Christ's at his coming.
[24] Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power.
[25] For he must reign, till he hath put all enemies under his feet.
[26] The last enemy that shall be destroyed is death.
[27] For he hath put all things under his feet. But when he saith, all things are put under him, it is manifest that he is excepted, which did put all things under him.
[28] And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all.

Believers in Jesus Christ still face physical death, but the stinger has been removed, because we will have a bodily resurrection just as Jesus did.

1 Cor. 15:50-58

[50] Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption.
[51] Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed,
[52] In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
[53] For this corruptible must put on incorruption, and this mortal must put on immortality.
[54] So when this corruptible shall have put on incorruption, and this mortal shall have put on immortality, then shall be brought to pass the saying that is written, Death is swallowed up in victory.
[55] O death, where is thy sting? O grave, where is thy victory?
[56] The sting of death is sin; and the strength of sin is the law.
[57] But thanks be to God, which giveth us the victory through our Lord Jesus Christ.
[58] Therefore, my beloved brethren, be ye stedfast, unmoveable, always abounding in the work of the Lord, forasmuch as ye know that your labour is not in vain in the Lord.

Heb. 2:6-15

[6] But one in a certain place testified, saying, What is man, that thou art mindful of him? or the son of man, that thou visitest him?
[7] Thou madest him a little lower than the angels; thou crownedst him with glory and honour, and didst set him over the works of thy hands:
[8] Thou hast put all things in subjection under his feet. For in that he put all in subjection under him, he left nothing that is not put under him. But now we see not yet all things put under him.
[9] But we see Jesus, who was made a little lower than the angels for the suffering of death, crowned with glory and honour; that he by the grace of God should taste death for every man.
[10] For it became him, for whom are all things, and by whom are all things, in bringing many sons unto glory, to make the captain of their salvation perfect through sufferings.
[11] For both he that sanctifieth and they who are sanctified are all of one: for which cause he is not ashamed to call them brethren,
[12] Saying, I will declare thy name unto my brethren, in the midst of the church will I sing praise unto thee.
[13] And again, I will put my trust in him. And again, Behold I and the children which God hath given me.
[14] Forasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death, that is, the devil;
[15] And deliver them who through fear of death were all their lifetime subject to bondage.

Although the enemy has not yet been cast into the lake of fire forever, his authority (or his power) has been taken away. His power over death is gone, and soon he is going to be gone as well!

The hounds of hell know NOW that they made a really bad move in crucifying Christ.

They were all clapping and dancing and singing and hollering while Jesus was being tried and beaten and dying on the cross, --  but it all came to abrupt end when he descended into Paradise at his death and proclaimed his victory.  

That was a terrible blow to them, and then the final punch was when He raised Himself back up to life again!

Now He ever lives to die no more!

1 Cor. 2:5-7

[5] That your faith should not stand in the wisdom of men, but in the power of God.
[6] Howbeit we speak wisdom among them that are perfect: yet not the wisdom of this world, nor of the princes of this world, that come to nought:
[7] But we speak the wisdom of God in a mystery, even the hidden wisdom, which God ordained before the world unto our glory:
[8] Which none of the princes of this world knew: for had they known it, they would not have crucified the Lord of glory.

Has the accuser of the brethren been cast down?

Rev. 12:1-10

[1] And there appeared a great wonder in heaven; a woman clothed with the sun, and the moon under her feet, and upon her head a crown of twelve stars:
[2] And she being with child cried, travailing in birth, and pained to be delivered.
[3] And there appeared another wonder in heaven; and behold a great red dragon, having seven heads and ten horns, and seven crowns upon his heads.
[4] And his tail drew the third part of the stars of heaven, and did cast them to the earth: and the dragon stood before the woman which was ready to be delivered, for to devour her child as soon as it was born.
[5] And she brought forth a man child, who was to rule all nations with a rod of iron: and her child was caught up unto God, and to his throne.
[6] And the woman fled into the wilderness, where she hath a place prepared of God, that they should feed her there a thousand two hundred and threescore days.
[7] And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,
[8] And prevailed not; neither was their place found any more in heaven.
[9] And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
[10] And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night.

I believe the event described in the verses above is in the past so I believe that the accuser has been cast down to the earth, meaning he no longer has access to the court of Heaven. He can no longer accuse us before God the Almighty but he and his minions can still accuse us down here in our own minds.

The Holy Spirit, Whom lives within our hearts, will convict us of sin but He will never condemn us for it.  He will never speak down to us. He will always encourage us. If, as a believer in Jesus Christ, you are being condemned in your mind that is the voice of the enemy!

The god of this world is God's topmost enemy, called the devil and satan.

He can no longer access Heaven's Court.  He is limited to this earth for now. But even if he could, his accusations would be powerless because of the blood of Jesus has covered God's saints.

He is a rebel prince without power. He still has influence but he has no Authority only what is given to him by man. If you are a child of God and you resist him, he runs. You must give him a place in your life in order for him to impact you. He cannot just take it.

We overcome him by the blood of the lamb and by the Word of our own testimony. Our Testimony is what we speak about ourselves!

Rev. 12:9-12

[9] And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
[10] And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night.
[11] And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death.
[12] Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time.

Here is the word of my testimony to the god of this world:

The Lord rebuke you. You have no authority over my life or in this world.  You are a defeated enemy awaiting final judgment. Jesus Christ, the son of God, is the King of kings and Lord of lords and Rightful Ruler of this Earth.  He is my Savior and my God!  I belong to Jesus -- that name that is above all other names.  Be gone!