Pathetic fallacy is a literary device that is used to create mood and atmosphere. It is the use of the weather or other atmospheric devices to reflect the mood and tone of the characters and their situation. It is used to help the reader understand the perspective of the character, and in many cases will be used to create a sense of foreboding.Pathetic fallacy is a literary device that is used to create mood and atmosphere. It is the use of the weather or other atmospheric devices to reflect the mood and tone of the characters and their situation. It is used to help the reader understand the perspective of the character, and in many cases will be used to create a sense of foreboding.