Nemesis

Nemesis (Νέμεσις in Ancient Greek) is the Greek goddess of balance, justice, karma, retribution, and vengeance. Her Roman counterpart is Invidia.

History
Nemesis is the daughter of the Titans Oceanus and Tethys. She appears chiefly as the avenger of crime and the punisher of hubris, being mainly the god of revenge or justice. The rest of her duties comes from that.

Percy Jackson and the Olympians
Although she was not seen in the series, she was mother to Ethan Nakamura and sided with Kronos when given the choice between siding with the Titans or the Olympians. She indirectly plays a major role in the series through her son as she made an exchange with him in order to bring respect to the minor gods. Although Ethan gave a much higher price than his required eye, the minor demigods and their parents were given their own cabins and general amnesty from Olympus.

Personality
Nemesis is seen as a cold and even cruel goddess whose ruthlessness is not exempt from even her own children, as shown when she took her son's eye as part of their pact. However, Nemesis does have a strong sense of honor as exemplified when she swore to her son that he would gain recognition from this same agreement. Overall, she seems to be both fair and intense.

Known Children

 * Ethan Nakamura (deceased)

Trivia

 * Nemesis is now often used as a term to describe one's worst enemy, normally someone or something that is the exact opposite of oneself but is also somehow similar.
 * Nemesis is also called the goddess of balance, she makes sure no man has too much good in his life to prevent hubris.
 * Her symbol is a set of scales.
 * On Rick Riordan's website, Nemesis is said to be sisters with the Roman form of Tyche, Fortuna. Whether this is true to the series or if Rick Riordan made a mistake is unknown.
 * It's odd that Ethan's burial shroud had scales under crossed swords when Nemesis is sometimes pictured with a whip in one hand and scales in the other.
 * The woman depicted on the New York state flag, holding the scales and sword, is believed to be based on Nemesis, however it is Dike the goddess of Moral Justice, or in some cases Dikes mother Themis.
 * A statue of Nemesis is sometimes seen in courts of law to represent balance or justice.