Princess Kathy is a princess played by Kathy. She is Prince Tyrone's sister.
She was responsible for turning her brother into a dark dragon and making him her slave, which in turn made her truly responsible for putting Princess Uniqua into eternal sleep. She did that because she was jealous of him being the ruler of his kingdom. She acts as the true antagonist of the first episode of The Backyardigans 2.0, The Sleeping Princess.