Nemesis is the Greek goddess of vengeance and divine retribution.
Appearance: Nemesis is usually portrayed as a winged woman carrying a sword and a set of scales. For images of Nemesis, click HERE, HERE. and HERE. (With regards to the last image, pay attention to what Nemesis is standing on.)
Lore: The daughter of Nyx (Night), Nemesis' main responsibility is to punish hubris, the arrogance of man. Hubris, a somewhat difficult word to properly convey, is the offense of mere mortals arrogantly behaving and boasting as if being equal to or superior to the gods. It is Nemesis' role to deal punishment to such foolish mortals and to keep humanity in it's place. Other than punishing hubris, Nemesis also plays an active role in the punishment of crimes and evil deeds, excessive pride, jilted or scorned love, and the excessive happiness or the taking granted of good fortune.
Nemesis In Culture: Nemesis has lend her name to the term arch-nemesis, a term denoting one's main enemy.