The mythical figure known to have a tragic flaw that leads to their downfall is Achilles from Greek mythology. Despite being a great warrior, Achilles possesses a flaw of excessive pride and vulnerability, famously manifesting in his heel. His rage and desire for glory often overshadow his judgment, consequently leading to his demise in the Trojan War. Achilles’ story serves as a cautionary tale about the dangers of hubris and the inevitable fate that befalls those who cannot temper their ambition, illustrating the complexity of heroism in mythology.