Hecate

Hecate or Hekate is the goddess of the night, darkness, cross-roads and magik or sorcery. She is the daughter of the Titan Perses and of Asteria and the mother of Scylla. She is called Agriope or "savage face".

Greek Goddess

Hecate is considered as one of the three goddesses of the moon on which she rules the dark side of the moon and it's terror. The other two are Artemis, also known as the virgin goddess of hunt and wild and Selene, which rules the moonlight or the bright side of the moon.
It's said that she has three faces facing all around to symbolize her great power over all. Thus, her three heads are sometimes depicted with that of a dog, a horse, and a lion. Sometimes she is also portrayed holding a torch or with a back of hounds. She was only worshipped at night and by torchlight. Dogs and black lambs were sacrificed to her then.
Hecate is goddess of the underworld, of chthonic rites, and of black magic as well as goddess of night and darkness. She may also have been a moon goddess representing its terror and darkness just as Diana represented the moonlight splendor. Medea was her priestess to whom she taught the art of magic.

Other Sources

These are the few other very informative sources about Hecate I founf online:

• Hecate (Wikipedia)
• Theoi Project:
  
  • Hekate Introduction and Myths
  • Hekate Goddess of: Greek Mythology
  • Cult of Hekate: Ancient Greek Religion
• Hekate/Hecate: Guardian at the Gate
• Hecate, Greek Goddess of Crossroads
• The Greek Goddess Hekate in Myth and Art
• Hecate - Greek Mythology

Shrines

• Hekate Shrine (Shrine of the Forgotten Goddesses)
• Hecate Shrine