Sindel

Perhaps my most hated character in the entire series, Sindel is the mother of Kitana and wife to emperor Shao Kahn. She made her first appearance in Mortal Kombat 3 and was always on the good side even with Shao Kahn as her husband. However though she resides with the fighters of Earthrealm, MK9 sees her align with her husband after he resurrects her from the dead. She turns against all of her allies including her daughter. There is not another character in Mortal Kombat to which I hate more, the few times I have been forced to play her, I have done badly.
Her fatalities are:
Migraine: Back, Forward, Down, Forward, X/Square
Mouthful: Back, Forward, Up, Y/Triangle