Ying and Yang are different. Bad and Good, evil and kind, rude and caring. But Ying and Yang always stick together. They changed, now that they are together. Now evil has some good inside, and good has some evil inside. Ying and Yang learned from each other. No matter what Ying and Yang will be together, forever. They were two opposites, opposites attract. Two different beings on this planet, conjoined with one another. Because of their different personalities.