'Chilling Adventures of Sabrina' shows Stolas is more than just Madam Satan's familiar, he's a demon

What best friends are to mortals, familiars are to witches and warlocks.
Sabrina Spellman's (Kiernan Shipka) familiar, Salem, is not unknown in the world of Archie Comics, but the only disappointment that came in the dark Archie Comics adaptation of 'Chilling Adventures of Sabrina' was that Salem, the black cat, did not talk as it should have. None of the familiars spoke, be it of Aunt Zelda, a dog and Aunt Hilda's, a spider. However, Madam Satan's (Michelle Gomez) familiar, a black crow, spoke in season one, much to the audience's surprise.
The familiar, going by the name of Stolas, tells Madam Satan, aka Miss Wardwell, "Forgive me Madame, but doesn't it seem that Satan is grooming Sabrina to reign at his side, not you?" This triggers Madam Satan and she ends up killing her familiar only to regret later.
In Part 2, the Dark Lord resurrects Stolas and gifts her familiar back for her services. Also because the Dark Lord wants her to get rid of Adam, Miss Wardwell's boyfriend, as Madam Satan grows fond of him. The return of Stolas is significant to the story because as demonstrated in episode 3 of 'Chilling Adventures of Sabrina,' part 2 play, Stolas has been with Lilith since the very beginning. In the play at the Academy of the Unseen Arts where Sabrina plays the role of Lilith and Agatha plays the role of Stolas, we see how the familiar has always guided her.
Lilith aka Madam Satan is the first wife of Adam, who had a fallout with God since she did not want to lie under him during copulation. Then she met Lucifer in the caves of Gehenna, which we saw in Sabrina's play. Stolas was always behind her.
But legend has it, Stolas is actually an independent demon, the 36th demon of the Ars Goetia. Goetia is a practice that includes the conjuration of demons, specifically the ones summoned by King Solomon.

Described as a raven or an owl, the illustration of Stolas was made famous by Louis Le Breton in a 19th-century demonology text. Stolas also takes the avatar of a man and is given the title of a Great Prince of Hell. Written in many of the demonology texts including Pseudomonarchia Daemonum, The Dictionnaire Infernal, and in Goetia, Stolas is described as a being with paramount knowledge on astronomy, the use of various precious stones and secrets of herbs and plants.
The 1583 edition of Weyer's Pseudomonarchia Daemonum says about Stolas; "Stolas is a great prince, appearing in the forme of a nightraven, before the exorcist, he taketh the image and shape of a man, and teacheth astronomie, absolutelie understanding the vertues of herbes and pretious stones; there are under him twentie six legions."
Then the 1904 translation of the Goetia by S. L. MacGregor Mathers describes Stolas similarly to the Pseudomonarchia Daemonum; "The Thirty-sixth Spirit is Stolas, or Stolos. He is a Great and Powerful Prince, appearing in the Shape of a Mighty Raven at first before the Exorcist but after he taketh the image of a Man. He teacheth the Art of Astronomy, and the Virtues of Herbs and Precious Stones. He governeth 26 Legions of Spirits."
Since Stolas is the prince of hell, it only makes sense that he is paired with Madam Satan, the queen of hell. Remember how Madam Satan introduced herself to frightened Principal Hawthorne? "I'm the Mother of Demons, the Dawn of Doom, Satan's concubine. I'm Lilith, dear boy. First Wife to Adam, saved from despair by a fallen angel. I call myself Madame Satan, in his honor."