When I think of demons I think of demon possession as demons do not respect anything other than their own master, Satan.
Mark 5:1-20 is the definitive passage on demon possession and its effects in the Bible. Some of the details about demons the Bible reveals in this passage are:
1. Devils want to be near dead human bodies or tombs (vs. 2, 3, 5).
2. They can cause unusual strength (vs. 3-4).
3. They can make a person unreasonable or immune to sensible persuasion (vs. 4).
4. They cause excessive crying (vs. 5).
5. They cause sadistic and masochistic behavior (vs. 5).
6. They have an affinity for heights (vs. 5).
7. They recognize Christ as "the Son of God" and appeal to Him (vs. 6-7).
8. They know they deserve torment and dread it (vs. 6-7).
9. They have names (vs. 9).
10. More than one can possess the same body (vs. 9).
11. They desire to stay in the same geographical region or "country" (vs. 10).
12. They would rather indwell an animal body than none at all (vs. 12).
13. They can cause animals to kill themselves (vs. 13).
14. They desire to be in a body when it dies (vs. 13).
15. They have a desire for water (vs. 13).
Mark 9:17-29 gives us even more details about devils:
16. They can cause dumbness and deafness (vs. 17, 25).
17. They cause rabid animal like behavior (vs. 18).
18. They can indwell from childhood (vs. 21).
19. They cause suicidal behavior (vs. 22).
20. They resist leaving a body and violently "rent" it while leaving (vs. 26).
21. There are different kinds of devils. Some have more power than others (vs. 29).
22. Some can only be removed by prayer and fasting of believer (vs. 29).
Ephesians 6:12 states Satan has a hierarchy of "devils" in his kingdom, "For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places." Thus some devils have more power and authority than others.
In Daniel 10:13 (as well as Mark 9:29) there is an example of this. "The prince of the kingdom of Persia" withstood the angel sent to explain Daniel's vision to him for 21 days. He could only break free when the angel Michael came and helped him overcome the powerful "prince." The "prince" may have been Satan, but more likely he was a very powerful devil.