Eris

is the goddess of Discord and an mortal enemy, as well half-sister of Athena.

Saint Seiya: The Movie


Eris comes to Earth after years of exile, seeking revenge against her enemy, Athena, who had drained all of Eris's life energy. This process reverted Eris to a younger form, but she regains her true body by in turn stealing Kido Saori's energy. She is, however, defeated by Pegasus Seiya, who uses the golden arrow of the Sagittarius Gold Cloth to stop the chaotic goddess.

Saint Seiya: Warriors of the Final Holy Battle
Eris appears as a spirit invoked by Lucifer as an ally to aid him. When he fails to steal the blood of Athena, Lucifer sends Eris, Abel and Poseidon to attack the Earth. After Lucifer is defeated, Eris is banished to the Underworld.

Saint Seiya: Saintia Shō
Main articles: Eris (Saintia Shō)

Followers
Eris has her own personal force of warriors, the Ghost Five, whose members were (probably) Silver Saints. However their strength exceeds the Silver Saint rank and they are regarded as Saints stronger than any saint of any era.

Trivia

 * Eris's antagonism towards Athena is likely inspired by the story of the wedding of King Peleus and the sea nymph Thetis (see also: Mermaid Thetis). Eris is specifically not invited to the feast. Angered, she takes revenge by crashing the wedding and rolling an apple of solid gold onto the table, with the words "For the Fairest" inscribed on it. Hera-Juno, Aphrodite-Venus and Athena-Minerva attempt to seize the apple, with each goddess claiming it belongs to her, as the most beautiful goddess. Zeus appoints Paris, a Trojan prince, to judge among them who should have it. Paris awards the apple to the goddess Aphrodite, earning Athena's undying hatred. This story is the primary cause of the Trojan War.
 * Eris is the name of a dwarf planet in the Solar System beyond Pluto. Its moon, Dysomnia, is named after one of the goddess's daughters.
 * In the Italian translation of the movie, Eris is called with her Roman name: Discordia (Eris is her Greek name) and she wants to kill Athena to use the latter body as a host, not simply to drain her energy from her.
 * Eris is commonly mistaken as a daughter of Zeus and Hera. In truth, Eris is the daughter of Nyx (the Night) in Greek Mythology. Nyx is also the mother of Hypnos and Thanatos, making both them and Eris siblings.