Allusion is a figure of speech, in which one refers covertly or indirectly to an object or circumstance from an external context. For example, you might say to one of your guy friends, "Don't act like Romeo in front of her." that would mean you are referencing to Shakespeare's "Romeo and Juliet."
A villain is an example of an archetype. The Incredibles, the character in question Syndrome. He's there to create the major conflict with the protagonist's the Incredible's family.
