Nyx is the Greek Goddess of the night. She is the daughter of Khaos and sister/wife to Erebos, God of darkness. Some sources list Nyx and Erebos as the parents of Hemera, Goddess of the day, and Aither, God of light, while others portray them as her siblings. Nyx has many children, including Hypnos (God of sleep), Morpheus (God of dreams), Eris (Goddess of strife), Nemesis (Goddess of retribution), Eros (God of procreation), Apate (Goddess of deceit), Thanatos (God of non-violent death), Moros (God of doom), Momos (God of ridicule), Dolos (God of trickery), Oizys (Goddess of misery), Hybris (Goddess of insolence), Geras (God of old age), Philotes (Goddess of friendship), Sophrosyne (Goddess of moderation), Epiphron (God of prudence), Eleos (Goddess of mercy), and Kharon (the ferryman of the dead). She also gave birth to several groups of spirits, such as the Moirai (the Fates), the Erinyes (the Furies), the Keres (Goddesses of violent death), the Oneiroi (spirits of dreams), and the Hesperides (Goddesses of the evening).

Nyx is usually depicted either as a woman with wings or as a charioteer, enveloped in dark mist. She is said to reside in a gloomy house far to the west, where she and her sister or daughter Hemera pass each other at sunrise and sunset.