mousy dark

Dark is a mystical entity passed down to each new male in the Niwa family when they turn 14, once they experience love. He remained dormant for 40 years because Daisuke's grandfather, who was Dark's previous host, had no male children. Females cannot inherit this role.
He is known as the phantom thief who consistently steals artworks created by the Hikari family. Unlike Daisuke, who has feelings for Risa, Dark fell in love with Riku. However, he is persistently pursued by Risa, who became infatuated with him after seeing him on the news. In the manga, it is shown that Dark started to develop feelings for Risa before he mentioned that he could "feel" her words "right here" in his heart. He uses Wiz (With) as his wings to avoid harming Daisuke, who would suffer if Dark used his actual black wings.
In the anime, Dark tells Risa that he only sees her as a reminder of her grandmother, whom he truly loved.
In the English version, Dark is referred to as the Phantom Thief Dark, while in Japanese, he is known as Kaitou Dark. His full name is Dark Mousy, though this name is only mentioned in the manga's character descriptions. In the anime, Krad calls him by this name once. His true name is Kokuyoku, and he represents one half of the exalted Black Wings, with Krad being the other half. It is evident that they were originally part of the same artwork but were separated at some point.