Using rule of thirds: a female angel standing on a hill with her head at the lower left intersection and her body down the vertical line, with her wings out, but tips pointed down behind her in "resting position". Attire would be a leather ankle-length battle skirt made of leather stips ~1.5 inches wide. And dragon scale mail for her upper half. Angle of the image should be 30-45 degrees to the right from directly behind her. At the upper right intersection should be the pearly gates, with the White City behind the walls with God's Palace prominently in the background, all of Heaven would be designed around and to accentuate the Palace and God's ego. Heaven can best be described as looming above her in the distance and imposing. The whole thing should be gray scale except her hair, which should be crimson. She's standing proudly and defiantly, ready to avenge her Mother and fix her Father's broken Creation, but the weight of the task of bringing war to Heaven should be the feeling the cover gives.
Along the left edge should be 'The Morningstar Chronicle' done vertically in Monotype Corsiva. Horizontal using that 'M', 'Mythmaker', in Century. I'm not sure if 'Mythmaker' should go right above the top horizontal line for rule of thirds, or closer to the top, but I would kind of like the title and subtitle to feel like half a cross.
Feel free to change the fonts if you don't think they play well with the image.