Kathy is a judge on season 2 of ACS.
Kathy is the older sister of former judge Katie. While she seemed a little similar to her sister in the first two episodes, by Episode 3, she starts to reveal her deeper personality... which for her judge-in-crime Rover is somewhat sadistic, such as her knowing about Bangle's "reveal" in the same episode and holding it against Rover.
Her judging role was played by Dolly12345 of Animal Crossing Community, and is currently played by maybear97 of YouTube. Kathy's birthday is April 16, the date when maybear97 joined YouTube.
PC's original plan for season 2 judging was to continue to use Rover for another season, while Katie was to be replaced by a new character. However, when wizard98(the player for Rover) chose to step down from judging at the end of ACCC and Dolly wished to stay, something would have to be done.
Kathy, the older sister of Katie, was then created to be the next judge so Dolly could resume her judging role, albeit as a new character. Because of Dolly's timespans of inactivity on ACC, maybear97 was cast to be Kathy's understudy in case Dolly did not respond in time for judging time. Since Dolly has not been active on ACC since July 2012, maybear97 officially took the role of judging in Episode 3.