Diana

Diana is one of the Main Villains of Jewelpet, she's a Black Munchkin cat with white paws who can use the forbidden dark magic called Dark Eyes Power and wears a frilly pink waistcoat, a pink bow, and also wears a silver heart-shaped necklace. She's Dian's younger sister, who got sealed by the Four Witches of Jewel Land many years ago due to her foolish acts. She was unsealed during the events of Episode 2 due to the Phantom Thieves, thinking it was the kitten they found. Her mission is to defeat the Four Witches of Jewel Land and rule both worlds by her power.

Although she can be snobbish, evil and sometimes jealous to Rinko, her magic however, is strong (which can be distinguished from the black to purple colored paw on the victim), casting it to a human or object in which the Jewel Charms were hiding, which can be broken by someone confessing their weakness. She always lets her minions, the Phantom Herb Thieves to do her bidding on stealing the Jewelpets and collecting them to break the seal that keeps Dian imprisoned. But time and time again, she and the gang failed on getting every single one of them. After the events of Episode 26, the Phantom Thieves betrayed her and Diana has gone solo on collecting the remaining Jewelpets.

But in the end, she successfully freed Dian from the Ice Prison. In Episode 52, she channeled her Jewel Power to the Jewel Stick along with the other Jewelpets and defeated Dark Dian, while opening her brother's heart to the truth that Jewelpets and Humans must co-exist in harmony and tell him he has friends in Jewel Land to accept him and Diana. After that, they both changed their ways. She has a fear of Bananas. Diana's name is based on Diamond and her birthday is on April 20th. Diana has a black version of the Jewel Pocketbook which she uses to identify which Jewelpet she will get. It was also used to unlock the Jewel Stick along with the one Rinko has. (source: Wikipedia)