unseen character

Television shows and stage plays sometimes include continuing characters — characters who are currently in frequent interaction with the other characters and who influence current story events — who are never seen or heard by the audience and only described by other characters. Often this starts as or evolves into a running gag or inside joke. Radio shows and plays also feature characters who never speak, and books feature characters who are merely referred to. Hidden characters appear in all varieties of fiction, but their prevalence is in televised programs. These can run for much longer than a movie or play (which usually last only a couple of hours), and unseen characters can take on special qualities.
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