Achilles, in Greek mythology, is the son of a mortal and a sea nymph. Achilles is the bravest, most handsome, and greatest warrior of the army of Agamemnon in the Trojan War. According to legend, after Achilles is born , his mother wants to protect him from harm so she holds him by the heel and dips him into the river Styx that has special powers. She forgets to wet the heel she holds him by, so after years he is killed by an arrow to that heel.