40 years ago, Dark was once in love with Rika. However, because of Dark's impending fate as a Phantom Thief and being non-human he and Rika couldn't be together. Regardless of her forbidden love, Dark remained the most important person in Rika's heart and so did Dark.
Dark only humored Risa's attraction because she reminded him of his lost love. Thinking what did her grandmother felt for Dark, Risa search and found a key to the estate statue, opening inside a letter detailing of her strong bond with Dark. From it, Risa found the strength to move pass her unrequited feelings for Dark.
- The Harada twins' grandmother's name, Rika, is a mixture of "Risa" and "Riku."
- Dark regards Daisuke's painting of blue snow as a coincide memory of his time with Rika.
- Rika only appears in the anime, not in the manga.