This cover I use as an introduction of the characters as well as hint about the series and chapters within.
There's Banusi (Anubis). It shows his signature weapon, purple color (a color hint of background if you know what purple means in history), his lucky earring (important to the story later on), the scar on his arm (part of his backstory as well as a few other scars hidden here), and cuffs in his hand that are about his back story and about what happens in the first book.
There's Dawn she's shown here without her skin condition (cosmetic spell she's been self conscious about it her whole life at the start of the series is only a few months into accepting it and showing it, so kinda a hint at backstory), shows her ears and tail (werecat), her outfit is meant to show a form of purity/enslavement due to her backstory, and her position is meant to hint at her role in a prophecy/love story.
Then there's Silver. He's shackled to a throne with a dented crown since he is the Full Moon King everyone wants to control and is shackled to a prophecy he doesn't want anything to do with. He is hiding his blind eye (backstory reason), is wearing clothes that used to be nice, but have worn down over time (hint and more of his back story), and is shown with his albino look (backstory reasons for white skin and hair).
The logo in the back is the logo that will be on the side spine if it makes it to print. The dark colors help with the overall mood of the series.