The hero who donned the mantle of "the greatest mortal" in Greek mythology is Achilles. Renowned for his unmatched prowess in battle during the Trojan War, Achilles symbolizes the archetype of the tragic hero, embodying both strength and vulnerability. His story illustrates themes of honor, fate, and the human condition. Achilles' legacy is marked by his complicated relationship with mortality and glory, ultimately culminating in his downfall, which represents the inevitable intertwining of heroism and tragedy.