When the Great Red Dragon [satan] is cast out of the Heavenlies there will be cast out with him all the principalities and powers and age rulers of darkness. Ephesians 6:12.
And the Heavens which now are not clean in His sight [Job 15:15], will be cleansed of evil powers.
There will be no universal peace unto the Lord comes back. Then the nations will beat their swords into plow-shares and the spears into pruning-hooks Micha 4:3.