A character who highlights by contrast the qualities of main is known as the?

A character who highlights by contrast the qualities of the main character is known as a foil.

Foils are often used in literature to emphasize the main character's strengths and weaknesses, making them more complex and relatable.

Here are some examples:

* Hamlet and Laertes (from Shakespeare's *Hamlet*)

* Romeo and Mercutio (from Shakespeare's *Romeo and Juliet*)

* Harry Potter and Draco Malfoy (from the *Harry Potter* series)

* Katniss Everdeen and Peeta Mellark (from *The Hunger Games* series)

These contrasting characters bring out the key qualities of the protagonist and make the story more engaging.