In Greek mythology, Erebus, or Erebos was often conceived as a primordial deity, representing the personification of darkness; for instance, Hesiod's Theogony places him as one of the first five beings to come into existence from Chaos.

Erebus features little in Greek mythological tradition and literature, but is said to have fathered several other deities by Nyx; depending on the source of the mythology, this union includes Aether, Hemera, the Hesperides, Hypnos, the Moirai, Geras, Styx, and Thanatos.

According to some later legends, Erebus was part of Hades, the underworld. It was where the dead had to pass immediately after dying. After Charon ferried them across the river Acheron, they entered Tartarus, the underworld proper. Erebus was often used as a synonym for Hades, the Greek god of the underworld. Also, Erebus was the name of the gloomy space through which souls passed on their way to Hades.

The perceived meaning of Erebus is darkness the first recorded
instance of it was "place of darkness between Earth and Hades.