She is training to master the mystic style of Woo Foo.She and her brother, Yang, train under Master Yo to master Woo Foo and to assure to the world that it is not foolish. In the episode "Night Fall", Yin shows that she can use Pretty Pink Paws of Pain. She is intelligent, cute, and sassy but quite stubborn. This may be because in the philosophy of Yin and Yang, Yin is the name of darkness, while Yang is the name of light. She has a pretty good sense of right and wrong, and usually does the right thing. In the episode "Old Softie", it is shown that before she finishes saying something, she can come up with different words to say something else; and in the episode "Dance, Dance Devastation", it is shown that she is a good rapper, dancer, and singer and that she can also speak some Spanish and German though this may have been because of the game controlling her.
Despite being half female, Yuck is often considered a "he" and lacks eyelashes, much like Yin and Yang's combined Aura.Yuck's general body shape is like Yin and Yang's: Short, round head and floating ears.