The legendary phantom thief Dark is a creature who has lived for centuries. Within every male in the Niwa family, Dark can come alive. And in Daisuke's case, change a person.
Every time Daisuke thinks of the girl he loves, he transforms into Dark. Unlike Daisuke, Dark is moody and a little evil. Dark lives to steal artwork and it appears that no one can stop him.
There are times when Daisuke has control of Dark's body and times where Dark has control of Daisuke's body. Dark doesn't like Daisuke's body as much as his own, but enjoys causing problems for Daisuke.
Dark seems to have feelings for Riku. His feelings of love transforms Dark back into Daisuke.
Much of Dark's past is a mystery, but there are those who know him from the past. With their interference, details of Dark's past are made clear.
Even though Dark and Daisuke aren't always thrilled with each other, Dark makes Daisuke a stronger person, and Daisuke makes Dark more aware of his actions. Together, they are able to grow and learn from each other.
