The hero who faced off against the Nemean Lion in Greek mythology, as part of his Twelve Labors, is Heracles (Hercules). This formidable lion was invulnerable, representing a seemingly insurmountable challenge. Heracles exemplifies strength, bravery, and determination as he ultimately defeats the beast through clever tactics. This myth underscores themes of heroism and the idea that true strength often lies not just in physical might but also in wit and resourcefulness.