Dian is the main villain of the first season of Jewelpet and Leon's Jewelpet partner in Jewelpet Tinkle, he's a Gray Maine Coon cat who with Diana, can also use forbidden dark magic, but in a powerful version called Obsidian Eyes Power. He wears a black round orb necklace and a black and red cape.

Dian's birthday is on January 20th and his name is based on the Igneous Rock Obsidian.

(Source: Wikipedia)