For other versions of this character see:
Despereaux resembled a humanoid spider, he had a seemingly normal face with three long spider like legs at the side of his head, he had a large spike in the center. His body was covered in shell like armor and had several other spider legs acting like a rib cage.
At an unknown point in time the demon Despereaux had fused with a young man who was in an unsettled state of mind. He attempted to take over the body, but the man proved to be pure of hart and he instead remained dominant and became Devilman Despereaux.