How did the soldiers in Saint saint seiya become ghost soldiers?

Five Gold Saints were killed when they attacked the Palazzo saint seiya 12. Then Hades revived their souls and wanted these powerful Gold Saints to help him. Hades also resurrected the previous generation of Pope, that is, Mu's teacher Aries. In order to bring the secret of Athena's holy clothes to Athena, the last pope and five dead saints promised Hades. They made a false promise with Hades, just to tell Athena to give her Athena's holy clothes. After that, six people with ghost soldiers attacked 12 Jindian. As a result, Pisces and Cancer were beaten back to the underworld by Aries Mu, but Mu couldn't beat his teacher, the last Pope, so Libra Tong Hu came down from the Five Old Peaks and personally fought his friend, the last Pope. Tong Hu, 200 years old, lost to the last generation of Pope who was given the body 18 by Pluto, and finally used it. Finally, it was the last pope who brought the secret of the holy garments to the statue of Athena, but Athena had gone to the underworld by then. So Hutong and Xiao Qiang went to the underworld. The last pope lost his soul, because it was time for Pluto to resurrect him.