Dull has raceless skin, short bright green hair and red eyes. He wears a cowboy attire which consists of a brown hat with a feather, a red scarf with yellow linings, and a short brown vest over a tucked in white buttoned shirt with folded sleeves. He sports a belt with a gun holster, brown folded gloves, cowboy pants and shoes. His right arm appears to be stitched and he is usually seen bleeding in all of the artworks he have appeared in. He also wields a black whip.
Not much is known about him.
Not much is known about his past.
Up to this day, Dull has only appeared in some of Deep-Sea Prisoner's Illustrations.
Nad is Dull's crush.  The two share romantic feelings.
- Dull is able to remove his head from his body.
- "Dull" is derived from "Dullahan."