Acharacter whose behavior and values contrast with the protagonist's

The correct answer is antagonist. 

An antagonist is a character in a story, novel or play who is a rival  of the protagonist (main person or lead character of a story) and has conflicting interests with the protagonist. An antagonist is often in direct opposition with the protagonist. Famous examples of antagonists include the character Tom Buchanan in The Great Gatsby, and Darth Vader in Star Wars.