Nyx

In Greek mythology, Nyx was the primordial goddess of the night. She was born of Chaos. She gave birth to Aether alone and Hemera, Moros, Charon, Eros and the Keres with her brother, Erebus. With Dionysus, she mothered Phthonus. She was also mother of Momus, Thanatos, Hypnos, the Hesperides, Nemesis, Apate, Philotes, Geras, the Fates.

Nyx's sister, Hemera, was the goddess of the day. Hemera left Tartarus just as Nyx entered it; when Hemera returned, Nyx left.

Her Roman equivalent was Nox. (Virgil V, 721)

Hesiod, Theogony; Aristophanes, Birds.