Astaroth (Supernatural)

Astaroth was a scary demon in the show Supernatural and was the mistress of Ruby. Astaroth was a normal black eyed demon but was very powerful. She was possibly a servant of Lilith. Astaroth comes from the Babylonian legends. Astaroth was possibly a human in Babylon who was a witch who became a demon in Hell upon her death.

Astaroth then gained normal demonic powers such as possession, longevity, flight, black magic and immunity to human weapons. Astaroth inspired fear in her colleagues. She sought to doom humans to Hell by making them witches. She set up a coven which the Winchesters investigated. They met Tammi, but she was so good at disguising herself, having been in disguise for perhaps a thousand years, and she charmed the brothers with her seemingly normal nature.

The brothers returned to check on the witches because though they didn't suspect Tammi they knew they were evil witches, and so the brothers were shocked when they found Tammi killing members of her coven using demonic powers. She revealed her demon eyes and she introduced herself as Ruby's mistress. She said that long ago in the Black Death, Ruby had sold her soul for protection from the plague. So Ruby had gone to Hell and been serving under Astaroth for years.

The brothers struggled against Astaroth, who killed all her coven. Then she tried to kill the brothers, but Dean stabbed her with Ruby's knife, killing her dead.