An archetype is a classic character that appears over and over throughout literature and myths. For example, there is the inexperienced hero, the wise oracle, or the lady in distress. In the story “The Masque of the Red Death” by Edgar Allen Poe I will give you two examples of archetypes.
Death personified is the first archetype. That means that death is a common character in literature. Think of the Grim Reaper, a character we all know. Near the end of the story, Death appears to Prospero and is described this way:
"When the eyes of Prince Prospero fell upon this spectral image (which with a slow and solemn movement, as if more fully to sustain its role, stalked to and fro among the waltzers) he was seen to be convulsed, in the first moment with a strong shudder either of terror or distaste; but, in the next, his brow reddened with rage." (fifth paragraph from the end)
A character with a fatal flaw is also an archetype. This means that a character has a personality flaw that causes him or her to make bad decisions. Prince Prospero’s fatal flaw is selfishness and pride. When everyone around him is dying, the prince holds a party.
But the Prince Prospero was happy and dauntless and sagacious. When his dominions were half depopulated, he summoned to his presence a thousand hale and light-hearted friends from among the knights and dames of his court, and with these retired to the deep seclusion of one of his castellated abbeys. (second paragraph)
By using archetypes, Poe makes his story seem timeless. We recognize what will happen to Prince Propsero, because we know he has a fatal flaw. We recognize Death, because we know he is a common spooky character.