The hero known for completing the Twelve Labors in Greek myths is Heracles, also known as Hercules in Roman mythology. He was a demigod, son of Zeus and Alcmene, famed for his incredible strength and heroic feats. The Twelve Labors were a series of challenges imposed on him as penance for a tragic crime. Each labor tested Heracles' resolve, intelligence, and physical prowess, culminating in legendary tales of his bravery. His journey symbolizes challenges faced by heroes and the struggle against overwhelming odds.