Vis-a-vis Deborah bat Omri:
Demons, as a rule, are in appearance the spitting image of certain deities worshiped by the pre-Christian population. They derive their appearance from the old god Pan. So, I figured that Deborah's father, the "Demon Asmodel," should not be an actual Judeochrislamic Demon/Jinn so much as the god Pan, still alive and kicking along with most of the old Indo-European deities, and attempting to protect the region of Earth from a rising galactic power, the Bizjarran Empire, which has already conquered a huge chunk of the galaxy and the region around Earth, though presumed barren, is fully encircled by Bizjarran rule.
Asmodel is the god Pan, god of shepherds under the Greco-Roman religion, and is not evil insofar as his very nature, he has just been (pardon the pun) demonized by the Church, due to Pan's very nature being chaos, whereas the Church sides with Order. Pan keeps his own name, but his daughter thinks that he is the Devil himself, which causes a great deal of friction whenever he attempts to speak to Deborah. Deborah is 60% Pan in terms of her genes, but among the 40% human genes she has is the genes coding for her physical form and body shape. Her internal organs and so on are more along the lines of Pan, and enable her to regenerate wounds, even wounds that would be fatal to ordinary humans. She has powers that modern-day people see as derived from either demons or the Hindu gods or something besides what it is, the old Greek gods, who are alive and well and rather amused at human depictions of them.
Zeus, or Thor, as he was known to the Germans, in particular makes an appearance in one of the first appearances of Deborah bat Omri, where she's reading Neil Gaiman's story about Mr. Wednesday, when Zeus himself shows up, on a Wednesday, no less. But regardless, in the Shades of Grey universe, the demons are merely the old gods, given dark names though they themselves are not dark, as such.
Pan, or Asmodel, is attempting to stop the Bizjarrans from noticing Earth, and Deborah later finds out that, and it starts to make her wonder if the 21st Century is really what it's cracked up to be.