On Earth-One, Mordru was the powerful leader of an alien world that developed from Gemworld, which in the 30th century became the seat of tremendous energies exerted by its inhabitants. Although vanquished repeated by his arch-enemies, the Legion of Super-Heroes, Mordru still posed a persistent threat to the lives of all in the era, and in the 20th century when he made a foray into that time drawing the combined Justice League and Justice Society in an attempt to make them his pawns in a mad bid for cosmic control
On Earth-Two, Mordru's doppleganger was a being known as Oracle or Aurakle, a heroic individual who like his twin could bend time to his will. Although more reclusive than evil doppleganger, Oracle did appear to aid a Legion on his world... Law's Legionnaires... who had been lost in time. Leading the Justice Society and visiting Justice League into seven past eras to retrieve the seven lost soldiers to achieving victory against the Iron Hand and his globe-spanning nebula hand. After this encounter, Oracle faded once more into the mists of time.