Driven by separation from his sister Seika after Mitsumasa Kido sent him to Greece, the orphan Pegasus Seiya endures six years of rigorous training under the Silver Saint Eagle Marin to earn the Pegasus Bronze Cloth. His signature technique, the rapid-fire Pegasus Meteor Fist, defines his early combat style. Returning to Japan and discovering Seika's disappearance, Seiya enters Saori Kido's sponsored Galaxian Wars tournament to aid his search. He forges bonds with fellow Bronze Saints Dragon Shiryu, Cygnus Hyoga, Andromeda Shun, and Phoenix Ikki while battling adversaries like the Black Saints and Silver Saints dispatched by the Sanctuary's corrupt Pope. His persistence, tactical ingenuity, and sheer willpower become hallmarks against superior foes. During the Sanctuary arc, Seiya awakens the Seventh Sense—a heightened Cosmo state enabling light-speed attacks and resilience—during battles such as his clash with Taurus Aldebaran. He temporarily wields the Sagittarius Gold Cloth, inheriting its legacy from the deceased Aiolos, to protect Athena. This arc culminates in exposing Gemini Saga as the false Pope and Athena's restoration. Confronting the reincarnated sea god in the Poseidon arc, Seiya's Pegasus Cloth turns gold after being anointed with Gold Saint blood, enhancing its defense during underwater battles against Poseidon's Marines. Athena seals Poseidon to conclude the conflict. In The Hades Chapter - Sanctuary, Seiya returns to a Sanctuary invaded by Hades' forces, where resurrected Gold Saints under Hades' control assault Athena. Seiya and his companions intervene despite resistance from surviving Gold Saints. After Athena sacrifices herself to reach the Underworld, Seiya's group follows, guided by the previous Pope Shion who provides Athena's divine armor. Later in the Hades conflict, Seiya attains the Eighth Sense, granting his soul autonomy in the Underworld and enabling physical resurrection. During the Elysion final battle, his Pegasus Cloth evolves into a God Cloth, granting flight and enhanced dimensional travel. This transformation allows him to confront Hades directly alongside Athena, suffering grave wounds from Hades' sword while defending her. In sequel manga like Next Dimension and the anime Saint Seiya Ω, Seiya appears as the Sagittarius Gold Saint, mentoring the new Pegasus Saint Kōga while continuing to serve Athena. His abilities expand to include energy projection, protective barriers for space travel, and advanced Cosmo manipulation, though he has not achieved the Ninth Sense associated with godhood.