The Helm of Darkness or Cap of Invisibility.[1] in Greek mythology, is a helmet that makes the person wearing it invisible.[2] It is also called the Cap of Hades or Helm of Hades.[3] It was said to be used by the goddess of wisdom, Athena, the messenger god, Hermes, and Perseus.[4]
According to mythology, it was made by the Cyclops. They had made a lightning bolt for Zeus, a trident for Poseidon, and the Helm of Darkness for Hades.[5] The helm of darkness is also mentioned in Percy Jackson.