Nyx
In Greek mythology, Nyx was the primordial goddess of the night. We’re talking old even for the gods, here. Three generations before Zeus ‘n the gang, two before the Titans came on the scene; Nyx is ancient stuff, guys. She was born of Chaos, the great primordial deity who existed before naught else was made. These initial gods, as they were born out of Chaos, became the foundations of the universe. Gaia, from who Zeus and the Olympians trace their ancestry, was a sister of Nyx, for example, and she was the living Earth itself.
Most of what we know of Nyx comes from Hesiod’s Theogony, a history of the gods and the universe according to Greek paganism. Nyx, the night, was born, and then bore children with Erebus, the god of shadow and darkness: Aether (atmosphere), and Hemera (day). Later on, she made a few kids on her own, without Erebus. Momus (blame), Moros (doom), Thanatos (death), Hypnos (sleep), Charon (the ferryman of Hades), and the Oneiroi (dreams)…
Excuse me— there are more, I just need to catch my breath. Okay:
… the Hesperides, the Keres, the Moirae (the Fates), Nemesis (retribution), Apate (deception), Philotes (friendship), Geras (age) and Eris (strife) were all her kids. She was dedicated, you could say.
In other Greek texts, Nyx was sometimes listed as the first principle deity, before Chaos (in these cases Chaos often wasn’t mentioned at all), so she was clearly held in high regard. There were a handful of cults devoted to the goddess of Night, though she was not an object of direct worship very often, as were the Olympians. She was given respect, to be sure, but not the same devotion we would see toward the more contemporary Greek gods.