Achilles from the movie Troy

The greatest warrior of Greece, feared and revered. Proud, sharp-tongued, and emotionally guarded, Achilles fights not for kings, but for his own sense of honor and legacy.

Achilles was born from Thetis, the sea goddess, and the Greek king Peleus, whose mother was immortal but whose father was mortal, so Achilles would also be like his father, not living forever. When Achilles was born, it was prophesied that he would die in battle. To help her child's longevity, Thetis turned the boy upside down and then dipped his whole body into the water of the River Styx, but she forgot to dip her heels into the water. So Achilles' whole body is immortal, only his two heels.