Satan was the first of God's creation to experience the knowledge of good and evil; God's plan for the sanctification of the children he would call to be his own. It is the realm designed to accomplish for God a nations of people who would undergo such tragedy in their lives they would cry out to be delivered, and by revelation of His plan for their redemption, would come to the realization it is God alone who saves, not only from the evil one but from ourselves. (Romans 8:20, 21)
As a spiritual being, Satan is removed from the horrors of his own evil that corrupts not only believers but even the people of God's common grace; those whom He has not chosen, but allows the good rain to fall on as well, yet becoming a vessel to be used by Satan against the children of the light. The spirit of rebellion works in the children of disobedience. However, what Satan intends for evil, God orchestrates for the good to those who love Him, to those who are called according to his purpose. While the devil and his demons manipulate the minds of those who dwell on Earth, attempting to deceive them from trusting in their only hope, Jesus (2 Cor. 4:4), he himself has been deceived, thinking he can ultimately win the elect to himself. That, however is also by design, to keep him engaged with God's chosen ones, for the purpose of sanctifying an unholy soul into an object of love, even in the face of evil's presence, that we may receive an everlasting kingdom where there will be no more tears, no more pain, no more evil. While there is still a Heaven and Earth, there will be seed time and harvest. Until the fullness of the gentiles is reached, all creation will suffer through Satan's ignorant defiance of God's miraculous plan for those He has called to Himself.
Satan has a strong rule and an even greater understanding over his own principality than than do God's own angels because, unlike the angels, Satan studies the depths of our carnality- of lust and contentment, weakness and strength- in order to enslave minds to the things of this world.
The battle though, is fought in the heavenly realms and is based on the knowledge of God's truths. However, truth and faith must work alongside each other. Should the enemy stand obstinate in the face of truth against a child of God, then it is only by their faith and endurance that those who belong to Jesus will find the victory in their present lives. Satan has been afforded the permission to test the faith of everyone that desires or claims to bring God's will into this present dominion, and only those who do not give up Jesus in the face of adversity will have victory over Satan.
Do not be deceived. You must go through fiery trials for the testing of your faith and the ultimate defeat of the enemy in your own life. While Satan roams the Earth looking for those he can destroy, your victory will be won in the battlefield of your own mind, relying on God's truths and resting in His promises which is our hope not yet seen, but presently belongs to those whom God has given the faith to possess.
"For I consider that the sufferings of this present time are not worth comparing with the glory that is to be revealed to us. For the creation waits with eager longing for the revealing of the sons of God. For the creation was subjected to futility, not willingly, but because of him who subjected it, in hope that the creation itself will be set free from its bondage to corruption and obtain the freedom of the glory of the children of God. For we know that the whole creation has been groaning together in the pains of childbirth until now. And not only the creation, but we ourselves, who have the firstfruits of the Spirit, groan inwardly as we wait eagerly for adoption as sons, the redemption of our bodies. For in this hope we were saved. Now hope that is seen is not hope. For who hopes for what he sees? But if we hope for what we do not see, we wait for it with patience." (Romans 8:18-25)