DEVILS AND SEDUCERS
Devils are fallen angels. Just like Adam, Lucifer wasn't content with the consciousness God gave him. He couldn't accept the limitations that belong to being a creature, and wished to be equal to God.
This was to become his downfall. Ever since he turned away from God, his only occupation is dragging along others in his fall. He tries to seduce everybody to make the wrong decisions.
We read in the bible how he suggests to Jesus he will donate the earth to Him (Luke 4, 1-13). Indeed, it often seems the devil is more in control of the earth than God. Therefore, some people sell their souls to the devil for temporary gain, as in the legend of dr Faust.
It's the devil's interest nobody believes he exists. That's why he stays in the dark. Most of the time, he disguises himself to become as inconspicuous as possible. However, God sometimes shows the devil to a chosen soul, as He did in 1917 to one of the seers of Fatima, little Francisco. The boy saw a stinking animal that resembled a billygoat.
The holy parish priest of Ars had much trouble with the devil, who made sleeping impossible with nocturnal noise and clamour. In the long run, the priest became immune to it: "The devil and I, we are just like comrades!"
Pope Leo XIII prescribed the following prayer: "Holy archangel Michael, defend us in our fight. Be our shelter against the evil and the tricks of the devil. We humbly beg you that God will make him feel His power. And thou, prince of the heavenly hosts, by the force of God, drive back into hell Satan and the other evil spirits, who are going around the world to the ruin of the souls. Amen."
Finally a song of Bob Dylan about the life of a man who's possessed by the devil, in this case a member of the mafia:
I pity the poor immigrant whose strength is spent in vain,
Whose heaven is like ironsides, whose tears are like rain,
Whose visions in the final end must shatter like the glass.
I pity the poor immigrant when his gladness comes to pass.