An Achilles's Heel was any type of weakness a character might have had.
Superman for example, was weakened by Green Kryptonite; making that his Achilles' Heel.
The term originated from Greek mythology, a reference to the legendary Achilles, who was a demigod and a soldier during the Trojan War.
References
- ↑ As seen in the comic story: The Cosmic Hit Man? (1976).