Given the sword of He by the Overlords of the Timeless Dimension on Trolla, Ro was told to "go forth and combat evil." During one such epic battle, he was infected by a techno-organic virus by Horde Supreme and sent through a vortex to the magic planet of Eternia. Once there, he was healed by Eldor in a mystical pool which absorbed his virus. In gratitude, He-Ro swore to help free Eternia from the Snake Men and Horde invaders. He defended the free people alongside the great King Grayskull, eventually bequeathing his sword to the King upon his heroic death.