Generate a close-up, 8K, cell-shaded, masterpiece illustration of a snarling robot, inspired by the unicron trilogy, with numerous limbs, black and orange dominant colors, and a cybertruck aesthetic. Incorporate a portcullis and a demonic, tempest-like atmosphere, reminiscent of Gerald Brom, James Jean, Krenz Cushart, Yuumei, and Death Burger's styles, trending on Artstation, with graffiti paint, fine details, and a golden ratio composition.