An Archetype is a way to define types of characters. Writers use them as models for specific types of characters. Not every archetype is perfect, but an archetypal character should have most of the characteristics. Additionally, some characters fit into numerous archetypes particularly as they grow and change. All heroes begin as initiates (though sometimes in before the book begins) and most mentors were or still are heroes.
The most common is the heroic archetype, which was followed by his or her nemesis (the villain or Shadow archetype). The hero and his or her nemesis batlle physically, emotionally, and intellectually. However the hero fights to help the innocent while the villain fights to gain wealth, power, etc,… Not all protagonists are heroes (or anti-heroes).
Archetypes in Harry Potter’s series: