According to some movies, the devil should be powerful. He should possess impure souls. The question we can ask ourselves is knowing why the devil exists. We can see that material is imperfect. But it grows the soul. But imperfect material means imperfect universe, therefore imperfect Souls, except origin.
Some people want the devil to exist. These are those whom do not want to ask questions about their live's usefulness. These people generally think that it is only about taking advantage of others. They encourage selfish pleasure, whereas there is better than entertainment, that is, happiness and joy.
To the opposite, the human is happy when he feels useful. The couple is the best demonstration. Our happiness is in fact making society, so that it comes back to ourselves, without going through the shortcut of animal selfishness. This way with others is so important to understand our personal happiness, linked to our fulfillment.
In fact the devil should exist only because God exists. Each soul creates its opposite, by the simple fact, for the other, to want to assert itself. The devil is due to our imperfection, whereas God has shown himself as a pure soul.
According to Jesus, the devil should exist only in our universe, not in God's universe, unless there is yet another universe. Jesus wanted to meet our universe's devil, going to the desert. The devil corrupts the pure soul, the child, the baby. The devil is especially among those whom
Gottfried Wilhelm von Leibniz (1700)
know its existence. Devil is due, according to Leibniz's monadology, to the imperfection of our universe and its material. Material creates time constraints with souls. That is why it does not exist in the same way in the universe of God. Indeed material can not move without time constraint, in the universe. God can do it, unless several souls take care of the earth alone.
My Notes
Read the Monadology of Leibniz, to better understand our universe. Write about that you do not understand.