The mythological hero known for his journey to the underworld to retrieve a loved one is Orpheus. In Greek mythology, Orpheus is a legendary musician whose love for his wife, Eurydice, drives him to the depths of Hades after her untimely death. Armed with his enchanting music, he persuades Hades to allow Eurydice to return to the living, but he must not look back at her until they reach the surface. His tragic tale emphasizes themes of love, loss, and the fragility of human life.