Royal Demons are the rarest demons to exist. They are the most powerful, and are always of the highest nobility. The only pure Royal Demons known to exist as of right now are Satan Lucifer, and his son Gabriel Lucifer.
Satan Lucifer was the first Royal Demon, and due to him originally being an Angel, they are the closest related demon species to Angels to exist. Satan evolved from Angel to Royal Demon from two things; 1) falling from heaven will deform an Angel, and the longer they are away from Heaven as a Fallen Angel the more they will deform. 2) The dark energy that was within him added to the deformation, which eventually evolved him into a Royal Demon.
Royal demons have dark grey skin with few markings. Their arms, of which they have four, fade to pure black with blackened veins being visible from under the skin. These same veins also appear around their eyes. They have cloven-hoofed feet, and small wings coming out from their ankles. They own four actual wings used for flight. Upon their head they will have six large horns. Their tails are extremely long, with a diamond-shaped tip. Their eyes also have dark grey sclera.