ST. SEIYA takes place in a not-so-distant future, after an unnamed catastrophe has disrupted the governments of the world. Asia's largest financial consortium, the "Graude Foundation", is sponsoring an international fight competition called "The Galaxian Wars". The prize is a set of "Gold Clothes" (armor) in the shape of Sagittarius, the centaur archer. Started and planned by the leader of the Graude Foundation, Mitsumasa Kiddo, the games are continued after his death by Saori, his granddaughter.

Approximately 16 years prior to the beginning of the show, a girl was born in Sanctuary, training camp for the Saints of Athena. She was identified as the current reincarnation of the Goddess of Wisdom. Unfortunately, unknown to anyone at the time, the Master of Sanctuary, her guardian and the one charged with running Sanctuary until Athena grew into her power, was killed by his twin brother, Gold Saint Gemini Saga. Saga had been possessed by the reincarnated spirit of Ares, who cheated this time by taking over an adult instead of a baby. Saga/Ares then attempted to kill the infant Athena. Sagittarius Aioros, another of Athena's Gold Saints, interferes and saves the child, escaping from Sanctuary with her. He makes his way to the ruins outside Sanctuary, where he and the child are found by Mitsumasa Kiddo, head of the Graude Foundation. Aioros tells him the child is Athena, and gives him his Gold Cloth to be given to his successor. Exhausted and injured by the previous battle with both Saga/Ares and then another of the Gold Saints, Aioros dies. Kiddo adopts the girl. A long-time martial arts enthusiast, he decides to train warriors and sponsor the Galaxian Wars as a means to decide who is worthy to become the new Sagittarius, and become Athena's bodyguard. Meanwhile, Ares, now disguised as the Master of Sanctuary, tells her Saints that Aioros has kidnapped Athena and that both Sagittarius and Athena have died. (Later he'll tell the Saints that Saori is an imposter and not really Athena). At this point Ares controls 10 of the 12 gold cloth; Saori has the Sagittarius cloth and the Libra Saint, who swore fealty directly to Athena in her previous incarnation, suspects what has happened and refuses to obey the Master.

Six years prior to the competition, the Foundation basically kidnapped 100 youngsters from various orphanages around the world and started training them as martial arts warriors. After winnowing them down to around 25, the remaining young warriors were sent to various training camps throughout the world. The training was very hard and difficult, and in many cases the trainers or others in the training camps were very cruel and brutal toward the youngsters. About a dozen (that the Foundation knows of) survived the camps, and won their "Bronze Clothes". (75% of the Saints, and the lowest ranking, are "Bronze Saints". Perhaps 20% are "Silver Saints", and there are 12 "Gold Saints" -- each one associated with one of the Zodiacal constellations. In the series, the majority of the Saints our characters run across are Silver. All the main characters start out as Bronze Saints. Oh -- just because they're called "Bronze Saints" doesn't mean their armor is bronze in color, although the "Gold Saints" DO have armor that is all gold colored.) Whomever of the Bronze Saints wins the competition will become the newest Gold Saint. There's much more to becoming a Saint than just being a martial arts expert, though.

Unknown to the contestants or the rest of the world, these Saints are actually only a few of the combatants in a major battle between the forces of the Greek gods Athena and Ares. Our Bronze Saints are all champions of Athena, and the opposition consists of Ares' servants.

As the story opens and we begin meeting the characters, the Galaxian Wars have started. Several of the Saints -- Seiya, Hyoga, and Ikki -- have not yet arrived...