Achilles is a famous, fictional hero from Greek mythology. He is a hero of the Trojan War and a central protagonist of Homer's Iliad. He was rumored to be a nearly invincible demigod, who was dipped into the River Styx by his mother, an immortal named Nereid Thetis. Where the water touched him, his skin became invulnerable. However, Nereid Thetis made the fatal mistake of keeping her hand around his heel during the event, making it his weakness. Achilles is most famous for slaying Trojan hero Hector outside of Troy. He is believed to have died afterward - killed by Paris, Hector's brother. He died when a poisoned arrow struck him in the heel, the only place that was vulnerable. This gave way to the popular phrase, "Achilles heel", to symbolize weakness.