Cover of a science fiction book, where you can see: a kingdom in a celestial world, where the city is made of golden crystal. A very tall, 40 years old white Nordic man with bright golden eyes, long white hair and beard, wears a long tunic and cape with crimson embroidery. A young Caucasian man, 18 years old, with long blond ponytail hair without beard and navy blue eyes, wears a long navy blue tunic and cape with gold embroidery. A young 18 years old woman with long blue hair wears a long ivory tunic and cape with navy blue embroidery. A young Caucasian man, 20 years old, with black hair and blood red eyes, wears a long black tunic and cape with vermillion red embroidery. Colorful and vibrant cover, minimalist typography, elegant sans-serif font, sleek lines, geometric shapes, characters, futuristic buildings, crystal city landscape, skyscrapers, palaces, mountains in the background, forest covering the mountains in the background with a silver hue. Ancestral abstract sculptures, a mist of blue and red smoke rises between the figures of the characters in the foreground and the background of the city and mountains. Ambient lighting, which provides depth of field, cinematic composition, 3/4 angle shot, softbox lighting, and high-quality realistic rendering. The four characters on the cover should be visible, similar to movie advertisements. It should convey drama, suspense, and intrigue.