A shadow itself represents the blocking out of light and, therefore, implies the existence of some lurking darkness or source of evil.

What is a shadow a metaphor for?

Carl Jung defined shadow as all of the parts of ourselves that we despise or loathe and therefore hide and avoid. It is impossible to run away or lose your shadow because ultimately, your shadow is a representation of you. No shadow can exist without a source of light.

What does shade symbolize in literature?

In literature and poetry, a shade (translating Greek σκιά, Latin umbra) is the spirit or ghost of a dead person, residing in the underworld.