Not much is known about Dark's past, except that he is a mysterious phantom thief. He is one half of the The Black Wings (Artwork), along with his archnemesis and other side, Krad. Dark seems to have a large reputation as a thief, as a large police force showed up to try and capture him after his 40-year slumber. He lives inside Daisuke Niwa and doesn't have many feelings of concern for him at first; but as the series goes on, he starts to show a soft side about Daisuke's health and well-being.