Nemesis

Nemesis (Νέμεσις in Ancient Greek ), also known as Rhamnousia/Rhamnusia is the Greek Goddess of Revenge and Balance.

History
In some myths Nemesis is the daughter of Oceanus, the sea Titan, yet in others she appears as the daughter of Nyx (personification of night), created from Chaos, the mass of energy at the beginning of time. She appears chiefly as the avenger of crime and the punisher of hubris. Her name in Greek means "to give what is due" therefore giving her the nickname, Justice.

Percy Jackson and the Olympians
Although she was not seen in the series, she was mother to Ethan Nakamura, and sided with Kronos when faced with choosing between siding with the Titans or siding with the Olympians. She gets her own cabin after The Last Olympian. She doesn't play a major role in the series, besides being the mother of Ethan Nakamura. At some point she made an exchange with her son that he would give up his eye in exchange for bringing minor gods respect and power. Ethan gave more than his eye, but the minor gods were given their own cabins and general amnesty around Olympus.

Nemesis is the symbol of balance, reason why she is depicted holding a scale at times.

Nemesis may have been one of the minor goddesses gathering for the Nine Muses concert in The Lightning Thief.

Personality
Nemesis is a cold hearted goddess, and isn't afraid to do radical exchanges with her own children, such as taking out one of Ethan's in one eye so he will receive power in return. Percy comments that he wouldn't want a mother like her. However "Nemesis always pays her debts, good or evil," says Ethan.

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. For example, Luke is frequently described as the nemesis of Percy. Nemesis is the goddess of balance, she makes sure no man has too much good in his life to prevent hubris. Her symbol is a scale. She is never mentioned giving happiness relying on other gods for that. Her purpose is usually misfortune to prevent too much happiness.
 * She is sometimes depicted with angel wings.