The shadow that Jung speaks of is another side of a person that people ignore or exist in the unconscious. In other words, it is the dark side of the ego. It refers to the inferior character excluded from the ego or the negative aspects within the ego such as attachment, anger, greed, jealousy, victim mentality, and selfishness hidden in human nature. However, Jung did not define the psychological contents according to an unchanging framework, but saw such shadows as something that moved and changed. In other words, not only do shadows have evil functions, but they are viewed to be possible to be changed into creative and good functions.
Then how can the apparently destructive, dangerous and negative effects of shadows be converted to creative ones? The key lies in how much one is interested and works on finding the unconscious of their ego to recognize the existence of the shadow. When one realizes this, changes in conscious occur and the negative effects of shadows can be retired.