The author of the Epistle to the Ephesians claims to be Paul writing while in prison. At first it might seem that the letter deals with the Angelic Powers and Devil as operating in two different spheres.
To begin with, we hear of the Powers. God’s force (dunamis) in favor of believers has been manifested in the working (energeia) of the might (kratos) of the strength (ischus) that He worked in Christ when He raised him from the dead and set him in the Heavens, far above every Principality (Arche) and Power (Exousia) and Force (Dunamis) and Dominion (Kuriotes) (Eph. 1.19-21). Then we hear of a single Ruler, not in the Heavens but in the Air:
In time past you walked according to the Age of this World, according to the Archon of the power (exousia) of the Air, the Spirit whose energeia now works in the sons of disobedience. (Eph. 2.2)
Next, back to the Powers: “Paul” says that his mission is to preach to the Gentiles and to make known the mystery hidden in God from the beginning of creation, “so that the manifold Wisdom of God might be made known, through the Church, to the Principalities and the Powers in the Heavens” (Eph. 3.10). Then on to Devil:
So, then, putting away falsehood, let all of us speak the truth to our neighbors, for we are members of one another. Be angry, but do not sin: do not let the sun go down on your anger, and do not make room for Devil. (Eph. 4.25-27)