Nanoha Takamachi first appeared as a minor character in the eroge visual novel "Triangle Heart 3" released on December 8, 2000. She first appeared, cast as a magical girl, on the merchandise CD "Triangle Heart 3 ~Lyrical Toy Box~" released on June 29, 2001. It was written by Masaki Tsuzuki, the creator of the "Magical Girl Lyrical Nanoha" franchise. Nanoha's first appearance in animation was in the first episode of the "Triangle Heart 3" OVA-adaptation series that released on July 24, 2003.