These designs are based on the nine choirs of angels as proposed by Pseudo-Dionysius the Areopagite, and on the visions of Saint Hildegard of Bingen.
The fallen Angel has been designed as a predator. Where the Angel protects and guides, he hunts and tears. Because of this, he has forward-facing eyes and claws. The wide torso and back compared to the slim waist and hips contribute to this appearance.
In addition to this, he has a starved and bony body. This, together with the pointed wing stumps, reveals the damage caused by the angel’s fall and makes the creature unsettling.
Protrusions on his head act as horns and identify the fallen Angel unmistakably as a demon. Thus, the fallen Angel and his angelic counterpart are opposites, but related. The form of the demon is clearly derived from the form of the angel, which refers to the demon’s lost membership in the nine choirs.