A Hero or a Heroine if female, is a characteristic of someone's work, in which they have been facing various dangers, bravery and strength, in order to make a heroic-deed or defeat the evil.
Opposite of a Hero, is the Villain. Which has the goals of destruction and harming others, in order to get pleasure from the acts and events. The Villain's main enemy is a Hero, which would fight against the Villain in order to keep everyone-everything safe.
The hero (Ancient Greek: ἥρως, hḗrōs), in Greek mythology and folklore, was originally a demigod, their cult being one of the most distinctive features of ancient Greek religion. Later, the hero (male) and the heroine (female) came to refer to characters who, in the face of danger and adversity or from a position of weakness, display courage and the will for helping others in trouble – that is, heroism – for some greater good, originally of martial courage or excellence but extended to more general moral excellence.