The devil has Angels and God has Angels. God's Angels are in heaven but the devil's Angels are on the earth. They are on the earth because the devil has the occupancy lease for the earth. God can visit, and he can send his Angels for periodic visits, especially when invited to do so. However, his lease ended many millennia ago when man decided that he wanted to experience both good and evil. When such a decision is made, the lease term is for a maximum of six thousand years. Six thousand years is one cycle in the universal calendar, just as one year is a cycle in the Gregorian calendar. I suspect this may be because it takes the moon six thousand years to rotate around the earth. Thus far, in all the years of us monitoring the lunar cycles, we have seen only one side of the moon which suggests a very slow lunar rotation that is perhaps close to completion.
When the six thousand years are complete, the leasehold terminates and the rightful owners have two possible options. They can renew the lease of the current occupant for another six thousand years, or they can transfer the lease to a different occupant. The only potential occupant who is seeking the leasehold for the earth is the Lord God of heaven and earth. We can choose him, or we can renew Satan's lease for another six thousand years.
When Satan knows that his leasehold is about to end, his customary tactic is fear. He induces fear into the rightful owners in order to cajole and deceive them into renewing his lease. We have the power to decide whether or not we will become victims of fear and subject the earth to another six thousand years of evil's reign.