Objection 1. It would seem that there is no precedence among the demons. For every precedence is according to some order of justice. But the demons are wholly fallen from justice. Therefore there is no precedence among them.
Objection 2. Further, there is no precedence where obedience and subjection do not exist. But these cannot be without concord; which is not to be found among the demons, according to the text, "Among the proud there are always contentions" (Proverbs 13:10). Therefore there is no precedence among the demons.
Objection 3. If there be precedence among them it is either according to nature, or according to their sin or punishment. But it is not according to their nature, for subjection and service do not come from nature but from subsequent sin; neither is it according to sin or punishment, because in that case the superior demons who have sinned the most grievously, would be subject to the inferior. Therefore there is no precedence among the demons.
On the contrary, On 1 Corinthians 15:24 the gloss says: "While the world lasts, angels will preside over angels, men over men, and demons over demons."
I answer that, Since action follows the nature of a thing, where natures are subordinate, actions also must be subordinate to each other. Thus it is in corporeal things, for as the inferior bodies by natural order are below the heavenly bodies, their actions and movements are subject to the actions and movements of the heavenly bodies. Now it is plain from what we have said (1), that the demons are by natural order subject to others; and hence their actions are subject to the action of those above them, and this is what we mean by precedence--that the action of the subject should be under the action of the prelate. So the very natural disposition of the demons requires that there should be authority among them. This agrees too with Divine wisdom, which leaves nothing inordinate, which "reacheth from end to end mightily, and ordereth all things sweetly" (Wisdom 8:1).
Reply to Objection 1. The authority of the demons is not founded on their justice, but on the justice of God ordering all things.
Reply to Objection 2. The concord of the demons, whereby some obey others, does not arise from mutual friendships, but from their common wickedness whereby they hate men, and fight against God's justice. For it belongs to wicked men to be joined to and subject to those whom they see to be stronger, in order to carry out their own wickedness.
Reply to Objection 3. The demons are not equal in nature; and so among them there exists a natural precedence; which is not the case with men, who are naturally equal. That the inferior are subject to the superior, is not for the benefit of the superior, but rather to their detriment; because since to do evil belongs in a pre-eminent degree to unhappiness, it follows that to preside in evil is to be more unhappy.
Source: Summa Theologica (New Advent)