Azure24 said:
In the prologue to the Book of Job, where Satan appears, together with other celestial beings or "sons of God," before the Deity, replying to the inquiry of God as to whence he had come, with the words: "From going to and fro in the earth, and from walking up and down in it. Does it not then characterize Satan as that a member of the divine council who watches over human activity, but with the evil purpose of searching out men's sins and appearing as their accuser. He is, therefore, the celestial prosecutor, lawyer who sees only iniquity; for he persists in his evil opinion of Job even after the man of Uz has passed successfully through his first trial by surrendering to the will of God, whereupon Satan demands another test through physical suffering. Is it not then evident from the prologue that Satan has no power of independent action, but requires the permission of God, which he may not transgress. He can not be regarded, therefore, as an opponent of God; and the doctrine of monotheism is disturbed by his existence no more than by the presence of other beings before the face of God.
Satan has no authority over the divine realm, though he was formerly Lucifer and had an authority before. When he was cast out of heavens, his dominion was just effective when the deceived angels heard him or sided in him but now, let us read who is the God of the demons. Is it satan or YHWH?
James 2:19 Thou believest that there is one God; thou doest well: the devils also believe, and tremble.
The belief of the demons is that there is one God and they tremble at that God.
More elaborately, we'll compare the conversation of satan to God in Job with the conversation of Jesus Christ and the Legion of devils.
And cried with a loud voice, and said, What have I to do with thee, Jesus, thou Son of the most high God? I adjure thee by God, that thou torment me not. Mark 5:7
For he said unto him, Come out of the man, thou unclean spirit. And he asked him, What is thy name? And he answered, saying, My name is Legion: for we are many. Mark 5:8-9
And all the devils besought him, saying, Send us into the swine, that we may enter into them. Mark 5:12
And forthwith Jesus gave them leave. And the unclean spirits went out, and entered into the swine: and the herd ran violently down a steep place into the sea, (they were about two thousand

and were choked in the sea.Mark 5:13
You can see parallel situations but different outcomes of Job's God-satan convo and Christ-legion convo in Mark.
God-satan conversation = God proves to satan that righteousness overcomes wickedness. Satan, a powerless envious spirit, caught God's attention through reasoning and by challenge.
Christ-legion conversation = Devils' idiotic minds drove them to request to Christ that they dwell on swine; Christ as an authority over them consented to their request (though he knew that swine are not capable to bear demons in their bodies, only human beings' bodies)
But if you really summarize at those conversations that satan has somewhat had an authority, well he did have but it occured only when he carried out away from the heavenly realm those who consented to his evil plans (remember Isaiah 14:13?). Now, satan is also considered by the world as god, but you know what? Satan has another god, but for sure, satan is not the God of the demons.