Disciples have power over satan and devils by the power of God through Jesus,
Luke 10:17 The seventy-two returned with joy, saying, “Lord, even the demons are subject to us in your name!”
10:18 And he said to them, “I saw Satan fall like lightning from heaven.
10:19 Behold, I have given you authority to tread on serpents and scorpions, and over all the power of the enemy, and nothing shall hurt you.
Rev 12:7 Now war arose in heaven, Michael and his angels fighting against the dragon. And the dragon and his angels fought back,
Rev 12:8 but he was defeated, and there was no longer any place for them in heaven.
Rev 12:9 And the great dragon was thrown down, that ancient serpent, who is called the devil and Satan, the deceiver of the whole world - he was thrown down to the earth, and his angels were thrown down with him.
Rev 12:10 And I heard a loud voice in heaven, saying, “Now the salvation and the power and the kingdom of our God and the authority of his Christ have come, for the accuser of our brothers has been thrown down, who accuses them day and night before our God.
Rev 12:11 And they have conquered him by the blood of the Lamb and by the word of their testimony, for they loved not their lives even unto death.
Again Christians, especially Spirit-filled Christians, have power over satan and devils - In my name they shall cast out demons - BUT this does not mean that satan and his demons do not rule this world.
The world belongs to evil both demonic and human. Look how infanticide is being made legal these days; and yet it was Christian morals that saved babies from being sacrificed to gods.