|Vadhyislavian witches are somewhere between this...|
What many are unaware of is that not all witches are the same; broadly speaking, they fall into one of two "schools," or "Covens."
Witches of the Green Coven draw power from pacts made with the Archfey; connected thus to the ebb and
Witches of the Red Coven draw power from pacts made with a powerful fiend; domineering and aggressive, Red Witches know what they want and are prepared to do almost anything to achieve it. Red Witches are more likely to live in deep seclusion in the forests and hills of Vadhyislavia than near villages, and especially in the many cavern systems honeycombing the countryside. Red Witches are frequently attended to by goblins, hobgoblins and ogres, using these monstrous creatures to further their wicked schemes. They occasionally ally with Night or Annis Hags.
It's rumored that a third school, the Black Coven, exists, though little to no evidence bears witness to this. Some claim that Black Witches work with or for Sea Hags, but from what source they draw power is a mystery.
Vadhyislavian Witches are really just 5E Warlocks with a name change and a few more spells added to their lists for flavor; Archfey-Pact Warlocks (i.e., Green Witches) add "Cure Wounds" and "Greater Restoration" to their spell-lists, while Fiend-Pact Warlocks (i.e., Red Witches) add "Inflict Wounds" and "Contagion."
Black Witches are Warlocks that have made a deal with a Great Old One; I want these to be half-pure rumor, half-so underground they might as well not really exist. They're deep background, and a player better give me a real good reason to open them up for play.