A 13-year-old boy, who is destined to become the Pegasus Bronze Saint in the future era. The main character in the series, trained since his early childhood to become a Saint, Koga is rebellious but also compassionate. He is still unaware of the purpose of having become a Saint in an era of peace, and has yet to discover his destiny. He meets Seiya, who teaches him the importance of friendship. Despite being capable of dealing Light-based attacks, Koga is later revealed to originally command the element of Darkness and be a vessel for Erebus (エレボス Erebosu), a power that was always being kept at bay by Athena's influence.