nyx

in the megaten series, nyx owns a creepy bar in ginza where other demons hang out and gives information to the protagonist. she is also creepy.

also,
In Greek mythology, Nyx was a primordial goddess that personified the night. She was a dark and shadowy figure that was created at the dawn of time and was the mother to many of the early gods. With her brother Erebus gave birth to Aether who personified the upper atomosphere and Hemera who personified day and on her own gave birth to many primordial gods associated with the night and darkness such as Hypnos the embodiment of sleep and Thanatos the embodiment of death as well as many many more. It is said that when Hemera enters Tartarus, Nyx leaves and when she returns, Hemera leaves, thus keeping a strict balance between day and night.