Demons, as you said, relate closely to disgraced gods. It's that they're lower beings than gods, and some prefer it that way. They have personalities like humans. They see us as "bargains". If we are to gain something out of working with them, they expect something to gain aswell, and they sometimes take more than they settled for.
Some, I've noticed, want as much attention as possible while others will want much seclusion and obscurity as possible.
Another thing to keep in mind, it's not appropriate to call them good or bad because they can act on whims or act for pure entertainment or fun for themselves.
They can be aggressive, some are pacified. They do see themselves higher up than humans, and they are, so treat them as a Noble!