Diancie first appeared in Diancie, Princess of the Diamond Domain. She was resting in a house when she heard a Pokémon crying out for help. She decided to follow the sound to see if she could be of assistance. In the nearby forest, she found a Pangoro stuck in a hollow tree. She tried to get it out, but to no avail. Then, her loyal Carbink servants arrived and helped in getting Pangoro free by stomping down on the tree. Right at that moment, a group of Ariados appeared and threatened Diancie and the Carbink. The Pangoro they helped stood up, however, and drove the Ariados off. Later, Diancie and the Carbink set off in the sunset, unaware they were being spied on by Millis Steel.
Diancie reappeared in Diancie and the Cocoon of Destruction.