The Gemini Gold Cloth is the Cloth of the Saints Saga and Kanon in Saint Seiya and Soul of Gold, Aspros and Defteros in Saint Seiya: The Lost Canvas, Cain and Abel in Saint Seiya: Next Dimension, and Paradox in Saint Seiya: Omega. It is of the highest class of the Cloths that Athena’s Saints wield, the Gold Cloths.
The Gemini constellation was based on the twins Castor and Pollux, who were born from Leda, but one was fathered by Zeus and another by Tyndareus. When Castor, mortal, died, Pollux asked to share their immortality, so they wouldn’t be separated. Zeus granted his wish by placing them in the sky as a constellation.
Saga and Kanon trained to be Saints in Sanctuary, years before the birth of the modern Athena, by an unknown master. The Cloth was likely kept in Sanctuary until a Saint worthy of wearing it was found. Saga was chosen as the main Saint and Kanon as his backup, but Saga sealed Kanon in the Stone Prison at Cape Sunion for trying to convince Saga to kill the infant Athena and the Pope. Despite this, Kanon’s words influenced Saga, and he killed the Pope, taking his place. He almost killed Athena, but Sagittarius Aiolos saved Athena and escaped with her. Sagabranded Aiolos as a traitor under the guise of the Pope, and Aiolos was killed by Capricorn Shura, but not before being able to pass SaoriAthena]] on to Mitsumasa Kido.
While Saga ruled as the Pope, Kanon escaped from the prison with some help from the infant Athena. He had found Poseidon’s Trident and went to Poseidon’s Temple, awakening Poseidon’s soul. Convincing Poseidon that he was Sea Dragon, Kanon planned to use Poseidon for his own ambitions when the time was right. Saga’s good side managed to make a good public face for the Pope, but Athena’s return only would add to growing suspicions. After numerous failed attacks, Sagitta Ptolemy struck Athena with a Golden Arrow, leaving her 12 hours to live. Sagafailed to stop the Saints in the Temple of the Gemini, and was even foiled in the Pope’s Chambers. Pegasus Seiya used the Aegis to both save Athena, and purge the evil from Saga. Begging Athena’s forgiveness, he killed himself in the Pope’s Chambers, wanting to die as a Saint of Athena.
Kanon used this time to prepare well, becoming Sea Dragon Kanon. The Gemini Gold Cloth waited in Sanctuary while Kanon’s plans were foiled and he learned the truth about what saved him. He risked his life to protect Athena, and she sealed away Poseidon’s soul. Kanon was allowed to return to Sanctuary as a Gold Saint by Athena during the Hades arc, despite reservations from Scorpio Milo. Saga returned with the Specters to attack Sanctuary in an attempt to bring Athena to the underworld and awaken her Cloth, and initially, Kanon fought him off from a distance using the same method Saga did back in the Sanctuary days. Saga disappeared after returning without Athena’s body, while Kanon lead Dragon Shiryu and Cygnus Hyogathrough Hell. Saga returned one last time to combine his powers with the rest of the Gold Saints, dying once more in the process in order to open the Wall of Lamentations. Kanon returned his Cloth to Saga before facing off against Wyvern Rhadamanthys one last time. He died by destroying his body and Rhadamanthys’ body with his Galaxian Explosion.
In Saint Seiya: Episode G, it is revealed that some sort of god being made Saga attempt to murder Athena and therefore, have Aiolos killed. Whether this was what also lead him to kill the Pope or not is not entirely clear. It seemed to be the machinations of those seeking to free Cronus and his weapon.
Lost Canvas/Next Dimension : Previous War
Aspros was the Guardian of the House of the Twins in The Lost Canvas, and was executed for treason, in plotting both the theft of Athena’s Cloth, and her murder. He would return to life as a Specter, and eventually meet his brother, Defteros, who took over as the Gemini Saint. Defteros had trained Tenma some, and fell as the Gemini Saint fighting his brother. Aspros returned to the role of Gemini Saint after that, having joined his body with Defteros. He defeated Youma permanently, before returning to the land of the dead.
During Next Dimension, Garuda Suikyo encountered a Gemini Saint attacking Shun and Tenma in the House of the Twins. He revealed himself to be Gemini Abel, the guardian of the Temple of the Gemini. During the battle, a second Gemini Saint, appearing to also wear a Gemini Gold Cloth as well, revealed himself to be Gemini Cain. The goodly Cain proved to be more powerful than his “brother”, but Abel returned, using his own illusion attack on Suikyo. The two brothers, almost seeming to share one body with two distinct minds, argue, Abel trying to corrupt Cain, claiming he tries to give his brother his heart’s desire. Abel used his “Genrō Maō Ken” on Suikyo, potentially to see him assassinate Athena. Phoenix Ikki arrives and is able to prove his story of having fought a Gemini Saint before. Cain tells Ikki of the curse of the Gemini Saints by the gods.