Are all the devils the same?
We have already seen that each devil sinned with a determined intensity. Moreover, each devil sinned in one or more sins in particular. The rebellion had its root in pride, but from that same root sprang up other sins. This is seen clearly in the exorcisms: there are devils that sin more in anger, others in self-worship, others in despair, etc. Each devil has his own psychology, his own peculiar way of being. There are loquacious ones, others are contemptuous, in one pride stands out the most, in another hate, etc. Although they all separated themselves from God, some are more evil than others.
Besides, we should remember that, as St. Paul tells us, there are nine hierarchies of angels. The superior hierarchies are more powerful, beautiful and intelligent that the inferior ones. Each anel is completely distinct from the rest. Angels do not have "races", -to use a zoological term-. Each one is complete in its species. Nevertheless, it is possible to group the angels into distinct large groups or hierarchies. Hierarchies are also called choirs, because it is as if they formed choirs which sing the praise of God. Their songs, obviously, are not with voices, but is rather the spiritual praise their wills give out by knowing and loving the Trinity.
When the angels fell, some fell from each of the nine hierarchies transforming themselves in demons. That is, there are devils that are virtues, powers, seraphims, etc. Even though they are devils, they conserve their power and intelligence intact.
As a result, it remains clear that a demoniacal hierarchy exists. One thing that has been seen in the exorcisms is that there exists a power of the superior devils over the inferior ones. What does this power consist of? It is impossible to know, since we can't see how a devil can oblige another to do something. They don't have a body which can be pushed or forced. Nevertheless, I have observed that a superior devil can oblige an inferior one not to leave a body during an exorcism. Even though the inferior devil suffers and wants to leave, the superior devil doesn't allow him. How this can happen between intangible spirits is something, I repeat, which escapes our understanding.